The appellee, Dorothy Chapman, brought suit against the appellant, Ortho Pharmaceutical Corporation, for personal injury suffered by her as a result of taking Ortho-Novum, an oral contraceptive manufactured by the appellant. Her complaint alleged liability on the theories of negligence, strict tort liability under Restatement (Second) of Torts § 402A (1965), and breach of warranty for Ortho's failure to adequately warn of the risk of thrombophlebitis attendant on use of Ortho's oral contraceptive. Judgment was entered upon a jury verdict in favor of Chapman, from which Ortho brings this appeal.
Ortho has raised numerous issues which will be dealt with as they arise in the course of our determination of the following major issues:
I. Whether the trial court erred in denying Ortho's motion for judgment on the evidence, challenging the sufficiency of evidence with respect to the inadequacy of the warnings and with respect to proximate cause.
II. Whether the trial court erred in refusing to give Ortho's tendered instructions numbered 2, 3, 6, 7, 9 and 10, in giving Chapman's tendered instructions numbered 2, 8, 4, 8, 9 and 10, and in the court's instructions numbered 1 and 3.
III. Whether the trial court committed reversible error in admitting into evidence a Federal Drug Administration-mandated "Patient Warning" which was not in use until August of 1970, in admitting an Or-tho-Novum 2 mg. package insert dated January, 1970, and in admitting an advertisement of Ortho-Novum from a medical periodical published after Chapman's doctor prescribed Ortho-Novum for Chapman.
I.
Because Ortho offered evidence on its own behalf, any error in overruling Or-tho's motion for judgment on the evidence at the close of Chapman's case-in-chief is waived. Lamb v. York, (1969) 252 Ind. 252, 247 N.E.2d 197; Meadowlark Farms, Inc. v. Warken, (1978) Ind.App., 376 N.E.2d 122; Ind. Rules of Procedure, Trial Rule 50(A). Therefore we need only review the propriety of the trial court's denial of Ortho's motion for judgment on the evidence at the close of all the evidence.
The rule in Indiana with respect to motions pursuant to T.R. 50, for judgment on the evidence, is that such a motion may properly be granted only if there is no substantial evidence or reasonable inference derived therefrom supporting an essential element of the claim: a complete failure of proof. When considering a motion for judgment on the evidence, the trial court must consider only the evidence and reasonable inferences favorable to the non-moving party. Huff v. Travelers Indem. Co., (1977) Ind., 363 N.E.2d 985; American Turners of South Bend v. Rodefer, (1978) Ind.App., 372 N.E.2d 516. The motion must be denied "where there is any evidence or legitimate inference therefrom tending to support at least one of the allegations. Where the evidence is such that the minds of reasonable men might differ, a directed verdict is improper, and the resolution of conflictive evidence is for the jury." (Original emphasis). Vernon Fire & Casualty Ins. Co. v. Sharp, (1976) 264 Ind. 599, 349 N.E.2d 173, 179. With this standard in mind, we examined the sufficiency of the evidence in support, first, of the existence of a defective condition unreasonably dangerous, and second, of the element of proximate cause.
a.
The theory of strict liability defined in the Restatement (Second) of Torts § 402A 1 has been expressly adopted as the
*545law in Indiana. Ayr-Way Stores, Inc. v. Chitwood, (1973) 261 Ind. 86, 300 N.E.2d 335; Perfection Paint & Color Co. v. Konduris, (1970) 147 Ind.App. 106, 268 N.E.2d 681; Cornette v. Searjeant Metal Products, Inc., (1970) 147 Ind. App. 46, 258 N.E.2d 652. A prima facie case is established by evidence of "(1) a purchase of (2) a defective product from (8) a seller engaged in the business of selling such a product (4) and the product reached him without substantial change in its condition and (5) that the product caused physical harm because of the defect." Ayr-Way Stores, Inc. v. Chitwood, supra, 300 N.E.2d at 340. The term "defective" requires some elaboration in this case. Chapman does not contend that there was any fault in the design and manufacture of Ortho-Novum, but rather claims that the lack of adequate warnings rendered it unreasonably dangerous.2
Section 402A, Comment k is particularly relevant in this case. It has been interpreted as creating an exception to the general rule of § 402A in the case of unavoidably unsafe products. Basko v. Sterling Drug, Inc., (24 Cir.1969) 416 F.2d 417, 425. Chapman argues that Comment k refers only to products for which there is "dire need and no safe alternative." We disagree. As the text of Comment k indicates, the question is whether marketing of the product is justified in light of the known risks. This involves balancing the public interest in the availability of such a product against the attendant risks. There is no dispute that oral contraceptives are potentially dangerous. For this reason they are "ethical drugs" available only by prescription.3 Nevertheless the public benefits from such a convenient and highly effective contraceptive. Therefore we have no difficulty in finding that oral contraceptives come under the protection of Comment k. See Carmichael v. Reitz, (1971) 17 Cal. App.3d 1958, 95 Cal.Rptr. 381, 398-40; Hamilton v. Hardy, infra, at 549 P.2d 1107; Lawson v. G. D. Searle & Co., (1976) 64 lll.2d 548, 1 Ill.Dec. 497, 356 N.E.2d 779, 782-83; Vaughn v. G. D. Searle & Co., supra, at 1248; Leibowitz v. Ortho Pharmaceutical Corp., infra, 307 A.2d at 457. See also Merrill, Compensation for Prescription Drug Injuries, 59 Va.L.R. 1, 7 (1978). Comment k emphasizes, however, that strict liability is avoided only when the product is accompanied by proper warnings:
k. Unavoidably unsafe products. There are some products which, in the present state of human knowledge, are quite incapable of being made safe for their intended and ordinary use. These are especially common in the field of *546drugs. * * * Such a product, properly prepared, and accompanied by proper directions and warning, is not defective, nor is it unreasonably dangerous. The same is true of many other drugs, vaccines, and the like, many of which for this very reason cannot legally be sold except to physicians, or under the prescription of a physician. (Emphasis added).
The rationale of this comment was explained in Borel v. Fibreboard Paper Products Corp., (5th Cir.1978) 498 F.2d 1076, 1088-89:
Strict liability may not always be appropriate in such cases because of the important benefits derived from the use of the product. This is especially so with respect to new drugs that are essential in treating disease but involve a high degree of risk. It may also be so with respect to other commercial products possessing both unparalleled utility and unquestioned danger. As a practical matter, the decision to market such a product requires a balancing of the product's utility against its known or foreseeable danger. But, as comment k makes clear, even when such balancing leads to the conclusion that marketing is justified, the seller has a responsibility to inform the user or consumer of the risk of harm. The failure to give adequate warnings in these circumstances renders the product unreasonably dangerous. The rationale for this rule is that the user or consumer is entitled to make his own choice as to whether the product's utility or benefits justify exposing himself to the risk of harm. Thus, a true choice situation arises, and a duty to warn attaches, whenever a reasonable man would want to be informed of the risk in order to decide whether to expose himself to it. {Citations omitted).
See also Incollingo v. Ewing, (1971) 444 Pa. 263, 282 A.2d 206. Thus, proof in this case of a defective condition unreasonably dangerous depends on the absence of proper warnings.4
In determining what is meant by "proper warnings," Comment k must be read together with Comment j.5 Comment j appears to impose an important limitation on liability under § 402A where warnings are in issue, by conditioning a seller's duty to warn on actual or constructive knowledge of the danger. The authorities are split in this respect. Those holding that knowledge is required include Midgley v. S. S. Kresge Co., (1976) 55 Cal.App.3d 67, 127 Cal.Rptr. 217; Christofferson v. Kaiser Foundation Hospital, (1971) 15 Cal.App.3d 75, 92 Cal. Rptr. 825; Oakes v. Geigy Agricultural
*547Chemicals & Co., (1969) 272 Cal. App.2d 645, 77 Cal.Rptr. 709; Tomer v. American Home Products, (Conn.1976) 368 A.2d 35; Woodill v. Parke, Davis & Co., (1978) 58 lll.App.3d 349, 15 Ill.Dee. 900, 374 N.E.2d 683; Cunningham v. Charles Pfizer & Co., (Okla.1975) 532 P.2d 1377; Bristol-Meyers Co. v. Gonzales, (Tex.1978) 561 S.W.2d 801; Crocker v. Winthrop Laboratories, (Tex.1974) 514 S.W.2d 429; and Ethicon, Inc. v. Parten, (Tex.Civ.App.1975) 520 S.W.2d 527. Those indicating that the law should assume knowledge include Hamilton v. Hardy, (1976) 87 Colo.App. 375, 549 P.2d 1099 (the parties stipulated that knowledge be limited to that at the time the product was being used; the court applied the Kimwood test of defectiveness based on assumed knowledge); Johnson v. Clark Equipment Co., (1976) 274 Or. 403, 547 P.2d 182; Phillips v. Kimwood Machine Co., (Or.1974) 269 Or. 485, 525 P.2d 1088; and Little v. PPG Industries, Inc., (Wash.App.1978) 579 P.2d 940. See also Wade, On the Nature of Strict Tort Liability for Products, 44 Miss. L.J. 825, 884-85 (1978). In the Little case, the court dismissed Comment j as "incongruous, since it shifts the emphasis away from the condition of the product (strict liability) and back to the reasonableness of the manufacturer's conduct (negligence)." 579 P.2d at 946. We reserve judgment on the broad issue, and confine ourselves to the question of whether knowledge is required where prescription drugs are concerned.
Comment k is replete with language indicating that the adequacy of a warning depends in part on what was known. In addition to the reference to "the present state of human knowledge," in the portion already quoted, Comment k states
It is also true in particular of many new or experimental drugs as to which, because of lack of time and opportunity for sufficient medical experience, there can be no assurance of safety, or perhaps even of purity of ingredients, but such experience as there is justifies the marketing and use of the drug notwithstanding a medically recognizable risk. The seller of such products, again with the qualification that they are properly prepared and marketed, and proper warning is given, where the situation calls for it, is not to be held to strict liability for unfortunate consequences attending their use, merely because he has undertaken to supply the public with an apparently useful and desirable product, attended with a known but apparently reasonable risk. (Emphasis added).
As stated in 3 L. Frumer & M. Friedman, Products Liability § 83.02(4],
[The Restatement has carved out an exception for drugs and vaccines Furthermore, before there can be hablhty predicated on the latter basis [not accompanied by appropriate warnings], Comment k requires that the manufacturer have knowledge of the danger, otherwise why recognize the factors of "lack of time and opportunity for sufficient medical experience."
The knowledge language of Comment j appears in the context of ingredients to which consumers are allergic. The comment then states "Likewise in the case of poisonous drugs, or those unduly dangerous for other reasons, warning as to use may be required." (emphasis added). Similar language appears in Comment h, which states that when a seller "has reason to anticipate that danger may result from a particular use, as where a drug is sold which is safe only in limited doses, he may be required to give adequate warning of the danger ." The language in these comments reinforces the sense of an exception to strict liability in the case of prescription drugs. The justification for such an exception is suggested by Dean Prosser:
The argument that industries producing potentially dangerous products should make good the harm, distribute it by liability insurance, and add the cost to the price of the product, encounters reason for pause, when we consider that two of the greatest medical boons to the human race, penicillin and cortisone, both have their dangerous side effects, and that drug companies might well have been deterred from producing and selling them. Thus far the courts have tended *548to hold the manufacturer to a high standard of care in preparing and testing drugs of unknown potentiality and in giving warning; but in the absence that this standard has not been met, they have refused to hold the maker liable for the unforeseeable harm. (Emphasis added.)
W. Prosser, Torts § 99, at 661 (4th ed. 197 1). Further explanation is offered in Oakes v. Geigy Agricultural Chemicals, supra, T7 Cal. Rptr. at 718, not a prescription drug case but nevertheless of interest:
The rationale of the strict liability rule is that the injured person is helpless to protect himself from the actually defective product. It is only reasonable therefore that as between the injured user and the one who places the product on the market the latter should bear the loss. The same rationale would apply to the marketing of a product which contains an ingredient which the manufacturer knows or should know "by the application of reasonable, developed human skill and foresight" is dangerous. But, in the view of this court, that is where the reason for the rule ceases and the rule of "strict" liability itself should stop. To exact an obligation to warn the user of unknown and unknowable allergies, sensitivities and id-iosynerasies would be for the courts to recast the manufacturer in the role of an insurer beyond any reasonable application of the rationale expressed above. (Citations omitted) (original emphasis).
We are persuaded that the duty to warn under Comment k does not arise until the manufacturer knows or should know of the risk. See also Basko v. Sterling Drug, Inc., supra, at 426; Davis v. Wyeth Laboratories, Inc., (9th Cir.1968) 399 F.2d 121, 129. In the case of drug manufacturers, the standard of constructive knowledge is that of an expert in that particular field. Reyes v. Wyeth Laboratories, Inc., (5th Cir. 1974) 498 F.2d 1264; McEwen v. Ortho Pharmaceutical Corp., (1974) 270 Or. 375, 528 P.24 522, 528. See Schenebeck v. Sterling Drug, Inc., (8th Cir. 1970) 428 F.2d 919, 922. As indicated in Basko, dates are "vitally important" with respect to the duty to warn. Because a manufacturer cannot be required to warn of a risk unknown to science, the knowledge chargeable to him must be limited to that of the period during which the plaintiff was using the product in question. 416 F.2d at 426; McEwen v. Ortho Pharmaceutical Corp., supra, 528 P.2d at 530.
A second important limitation on liability in this context, not mentioned in the comments, applies to manufacturers of ethical drugs. Since such drugs are available only by prescription, a manufacturers duty to warn extends only to the medical profession, and not the ultimate users.6 See Reyes v. Wyeth Laboratories, supra; Hoffman v. Sterling Drug, Inc., (8rd Cir. 1973) 485 F.2d 182; Basko v. Sterling Drug, Inc., supra; Davis v. Wyeth Laboratories, Inc., supra; Sterling Drug, Inc. v. Cornish, (3th Cir.1966) 370 F.2d 82; Stottlemire v. Cawood, (D.C.D.C.1963) 213 F.Supp. 897; Love v. Wolf, (1964) 226 Cal.App.2d 878, 38 Cal. Rptr. 183; Magee v. Wyeth Laboratories, (1963) 214 Cal. App.2d 340, 29 Cal.Rptr. 322; Hamilton v. Hardy, (Colo.App.1976) 549 P.2d 1099; Smith v. E. R. Squibb & Sons, Inc., (1976) 69 Mich.App. 375, 245 NW.2d 52; Mulder v. Parke Davis & Co., (1970) 288 Minn. 332, 181 N.W.2d 882; Johnston v. Upjohn Co., (Mo.App.1969) 442 S.W.2d 93; Hines v. St. Joseph's Hosp., (1974) 86 N.M. 763, 527 P.2d 1075; Parker v. State, (1951) 201 Misc. 416, 105 N.Y.S.2d 785; Vaughn v. G. D. Searle & Co., (0r.1975) 536 P.2d 1247; McEwen v. Ortho Pharmaceutical Corp., supra; Leibowitz v. Ortho Pharmaceutical Corp., (1978) 224 Pa.Super. 418, 307 A.2d 449; Gravis v. Parke Davis & Co., (Tex.Civ.App.1973) 502 S.W.2d 8638; Terhune v. A. H. *549Robins Co., (1978) 90 Wash.2d 9, 577 P.2d 975. The rationale for this exception to the Restatement's general rule is that
Prescription drugs are likely to be complex medicines, esoteric in formula and varied in effect. As a medical expert, the prescribing physician can take into account the propensities of the drug, as well as the susceptibilities of his patient. His is the task of weighing the benefits of any medication against its potential dangers. The choice he makes is an informed one, an individualized medical judgment bottomed on a knowledge of both patient and palliative.
Reyes v. Wyeth Laboratories, Inc., supra. The court in Terhune v. A. H. Robins Co., supra, elaborates further:
The reasons for this rule should be obvious. Where a product is available only on prescription or through the services of a physician, the physician acts as a "learned intermediary" between the manufacturer or seller and the patient. It is his duty to inform himself of the qualities and characteristics of those products which he prescribes for or administers to or uses on his patients, and to exercise an independent judgment, taking into account his knowledge of the patient as well as the product. The patient is expected to and, it can be presumed, does place primary reliance upon that judgment. The physician decides what facts should be told to the patient. Thus, if the product is properly labeled and carries the necessary instructions and warnings to fully apprise the physician of the proper procedures for use and the dangers involved, the manufacturer may reasonably assume that the physician will exercise the informed judgment thereby gained in conjunction with his own independent learning, in the best interest of the patient. It has also been suggested that the rule is made necessary by the fact that it is ordinarily difficult for the manufacturer to communicate directly with the consumer. (Footnote omitted).
In summary, a proper warning under Comment k in the context of the facts at bar, communicates a risk attendant on the use of the product which is known to experts in the field during the period in which the product is used. It need only be directed to doctors, not patients who are the ultimate users.
An absence of proper warning which may render a product unreasonably dangerous can range from a complete absence of any warning to a warning which is given but is inadequate. See Basko v. Sterling Drug, Inc., supra, at 426. In connection with the latter range, the test of propriety has been expressed as whether the warnings given are "reasonable under the circumstances." Sterling Drug, Inc. v. Yarrow, (8th Cir.1969) 408 F.2d 978, 998. Sterling Drug, Inc. v. Cornish, supra. In arriving at this conclusion, the court in Yarrow compared § 402A with § 388 of the Restatement.7 Section 888 in essence restates the common law cause of action for failure to exercise reasonable care to inform users of the dangerous qualities of a chattel. Compare Section 388, with Ft. Wayne Drug Co. v. Flemion, (1931) 93 Ind.App. 40, 175 N.E. 670, 672. The court in Yarrow found that classifying a breach of duty to warn under either § 388 or § 402A was unimportant because the standard under either is the *550same: the effort to warn must be reasonable under the circumstances.
The peculiar nature of an action based on absence of proper warning under § 402A has resulted in further comparisons with negligent breach of duty to warn. It has been stated that the fundamental difference between strict liability and negligence is the requirement of actual or constructive knowledge of the defect on the part of the seller. See Wade, On the Nature of Strict Tort Liability for Products, 44 Miss.L.J. 825, 834-85 (1973); and Keeton, Product Liability and the Meaning of Defect, 5 St. Mary's L.J. 80, 87-88 (1978). Thus, those authorities finding knowledge necessary in connection with the duty to warn under § 402A have frequently noted that there is no practical difference between the two theories in this context. In Basko v. Sterling Drug, Inc., supra, at 426, the court found that the exception created by Comment k in the case of unavoidably unsafe products "simply adopts the ordinary negligence concept of duty to warn." In Midgley v. S. S. Kresge Co., supra, 55 Cal.App.3d at 74, 127 Cal. Rptr. at 221, the court stated that "As we recognized in Oakes the prerequisite of actual or constructive knowledge of product dangers as a limitation upon duty to warn thereof engrafts concepts of substantive negligence law onto the element of defect in cases of strict liability for failure to warn." In Merrill, Compensation for Prescription Drug Injuries, supra, at 31, it is stated that negligence and strict liability are "functionally interchangeable in most drug cases." It has been held erroneous to instruct a jury on both theories. Rainbow v. Albert Elia Building Co., (1975) 49 A.D.2d 250, 878 N.Y.S.2d 928; Skaggs v. Clairol, Inc., (1970) 6 Cal.App.3d 1, 85 Cal. Rptr. 584. In Anderson v. Klix Chemical, (1970) 256 Or. 199, 472 P.2d 806, the Supreme Court of Oregon concluded there was no difference between strict liability and negligence where liability is based on the absence of proper warnings. Soon thereafter, the same court expressly overruled Anderson on that issue. In Phillips v. Kim-wood Machine Co., supra, the court found certain differences:
In a strict liability case we are talking about the condition (dangerousness) of an article which is sold without any warning, while in negligence we are talking about the reasonableness of the manufacturer's action in selling the article without a warning. The article can have a degree of dangerousness because of a lack of warning which the law of strict liability will not tolerate even though the actions of the seller were entirely reasonable in selling the article without a warning considering what he knew or should have known at the time he sold it.
A way to determine the dangerousness of the article, as distinguished from the seller's culpability, is to assume the seller knew of the product's propensity to injure as it did, and then to ask whether, with such knowledge, he would have been negligent in selling it without a warning.
525 P.2d at 1089. The court acknowledged that the language and concepts of reasonableness used to determine unreasonable risk under § 402A are the same as those in negligence cases, and that "the same process is going on in each instance, 1. e., weighing the utility of the article against the risk of its use." Id. The distinction lay in "the manner in which the decisional functions are distributed between the court and the jury." 525 P.2d at 1089. The Phillips court quoted extensively from Wade, Strict Tort Liability of Manufacturers, 19 S.W.LJ. 5 (1965) in which Professor Wade elaborates the point that in some kinds of cases under § 402A, where social policy issues are particularly important, court's control of jury action is more extensive than in ordinary negligence cases. The court in Phillips noted that the considerations enumerated therein were for the use of a court in determining whether a plaintiff's case warrants submission to a jury: "If such a case has been made out, then it is submitted to the jury for its determination under instructions as to what constitutes a 'dangerously defective' product, much in the same manner as negligence is submitted to the jury under the 'reasonable man' rule." 525 P.2d at 1040. In Johnson v. Clark Equipment *551Co., supra, 547 P.2d at 142 n. 12, the Kim-wood case is interpreted as stating that strict liability "assumes that the particular danger presented was foreseeable by the manufacturer." It thus appears that the difference discovered in Kimwood is that actual or constructive knowledge need not be proved. Otherwise, the tests of culpability and dangerousness are identical.
This question has also arisen with respect to breach of implied warranty. Numerous courts have found no practical difference between the theories of strict liability under § 402A and breach of implied warranty where the absence of proper warning is in issue. See Davis v. Wyeth Laboratories, Inc., supra, 399 F.2d at 126; Basko v. Sterling Drug, Inc., supra, at 427, and the cases cited therein. See also, Withers v. Sterling Drug, Inc., (S.D.Ind.1970) 819 F.Supp. 878, 883 (seeks same remedy under a different label); Fruehauf Trailer Div. v. Thornton, (1977) Ind.App., 866 N.E.2d 21, 28 (same evidence supports either action); and Gregory v. White Truck & Equipment Co., (1975) 163 Ind.App. 240, 323 N.E.2d 280, 289.
In Smith v. E. R. Squibb & Sons, supra, the court upheld a trial court's refusal to submit a case based on absence of proper warning to the jury on the theory of breach of implied warranty in addition to negligence:
We do not imply that there is not a valid distinction, in a products liability case, between the theory of implied warranty and the theory of negligence. Under the particular facts of this failure to warn case, however, it becomes a distinction without a difference since the standard and the proofs necessary to recover are identical under both theories. We find it far less confusing to discuss the duty to warn in terms of reasonableness right from the start rather than to become involved in the more cumbersome warranty concepts. As the California Court of Appeals said in Love v. Wolf [226 Cal. App.2d 378, 88 Cal.Rptr. 183]:
"No rule of strict liability (whether expressed in terms of breach of implied warranty, or in terms of a breach of a duty of care in tort) has been applied to a failure adequately to warn of the dangers inherent in the use of a drug. * * * We have already held here there is a duty to exercise reasonable, care to warn against the known dangers of a product. * * * There would appear, however, to be no sound basis to attempt to restate these rules in the terms of the law of contract warranties nor to extend them to impose a greater degree of care than that already stated." Love v. Wolf, supra, 226 Cal.App.2d at pp. 402-4083, 38 Cal. Rptr. at pp. 197-198.
We find, therefore, that the trial court did not commit reversible error in submitting the case to the jury on the negligence theory alone.
245 NW .2d at 56-57.
In Indiana, negligent breach of the duty to warn has been described as follows:
[T]he common law as applied to a vendor who sold dangerous merchandise is well stated in Wellington v. Downer Oil Co., 104 Mass. 64, as follows: "It is well settled that a man who delivers an article, which he knows to be dangerous or noxious, to another person, without notice of its nature and qualities, is liable for any injury which may reasonably be contemplated as likely to result, and which does in fact result, therefrom, to that person or any other, who is not himself in fault.
Fort Wayne Drug Co. v. Flemion, supra, 175 N.E. at 672. Except for the mention of the contributory negligence defense, this language effectively describes the cause of action under § 402A with the attendant limitation of knowledge imposed where prescription drugs are concerned. Nevertheless, we agree with the above-cited authority that there is a difference between negligent breach of duty to warn and breach of warranty or strict liability based on the absence of proper warnings. If nothing more, § 402A requires one conclusion of law in addition to a finding of negligence: the manufacturer being negligent in endeavoring to warn of a risk, the product is in a *552"defective condition unreasonably dangerous." This conclusion requires no additional finding of fact by the jury, therefore we agree that in some cases it may be unnecessary to give instructions on all three theories. A fundamental premise of the jury system is that a jury will understand a court's instructions. However, there is no harm in simplifying matters where the differences between these three theories are of no benefit to the plaintiff, and might result in unnecessary confusion.8
In light of these similarities, the court in Sterling Drug, Inc. v. Yarrow, supra, employed negligence concepts in analyzing reasonableness of warnings. Following the guidelines of § 388, Comment n, the court held that what is reasonable is proportionate to the gravity of the risk involved. 408 F.2d at 994. Thus, the trier of fact in that case could reasonably find the harm risked so great that any warning less than the "best" or "most effective" is not reasonable under the circumstances. Spruill v. Boyle-Midway, Inc., (4th Cir. 1962) 808 F.2d 79, a negligence case based on the failure to adequately warn of the poisonous character of the defendant's furniture polish, provides a detailed definition of an adequate warning:
If warning of the danger is given and this warning is of a character reasonably calculated to bring home to the reasonably prudent person the nature and extent of the danger, it is sufficient to shift the risk of harm from the manufacturer to the user. To be of such character the warning must embody two characteristics: first, it must be in such form that it could reasonably be expected to catch the attention of the reasonably prudent man in the circumstances of its use; secondly, the content of the warning must be of such a nature as to be comprehensible to the average user and to convey a fair indication of the nature and extent of the danger to the mind of a reasonably prudent person.
308 F.2d at 85. A similar definition appears in Bituminous Casualty Corporation v. Black and Decker Manufacturing Co., (Tex. Civ.App., Dallas 1974, writ ref'd n.r.e.) 518 S.W.2d 868, 872-78:
(1) [I)t must be in such form that it could reasonably be expected to catch the attention of the reasonably prudent man in the circumstances of its use;
(2) the content of the warning must be of such a nature as to be comprehensible to the average user and to convey a fair indication of the nature and extent of the danger to the mind of a reasonably prudent person. the question of whether or not a given warning is legally sufficient depends upon the language used and the impression that such language is calculated to make upon the mind of the average user of the product. Implicit in the duty to warn is the duty to warn with a degree of intensity that would cause a reasonable man to exercise the caution commensurate with the potential danger. A clear cautionary statement setting forth the exact nature of the dangers involved would be necessary to fully protect the seller. (Emphasis added).
Thus, a warning may be inadequate in factual content, inadequate in the expression of the facts, or inadequate in the method by which it is conveyed. See McEwen v. Ortho Pharmaceutical Corp., supra, 528 P.2d at 529.
To summarize, a product which is faultlessly designed and manufactured may be nevertheless unreasonably dangerous within the meaning of § 402A if not accompanied by proper warnings. A manufacturer can only be required to warn of risks known during the time in which the plaintiff was *553using the product in question, however he is charged with the knowledge of an expert in that field. In the case of ethical drugs, the manufacturer's duty is discharged if adequate warning is given to doctors, who act as "learned intermediaries" between the manufacturer and the ultimate user. To be adequate, a warning must be reasonable under the cireumstances. As a practical matter, this is determined by application of negligence theory.
As proof of the inadequacy of Ortho's warnings, Chapman offered into evidence the full text of the written warnings in question9 and expert testimony as to the state of knowledge in the medical profession at the time. Ortho argues that the plaintiff's expert was not qualified to give an expert opinion as to the adequacy of the warnings since he had no special training or experience in reading and writing warnings. This is not the test:
The true rule appears to be fairly stated in the case of Isenhour v. State, 1901, 157 Ind. 517, 528, 62 N.E. 40, 44, 87 Am.St. Rep. 228, in which this court said: "Courts have never undertaken to set up a standard of scientific knowledge by which the competency of a witness may be determined, and have not gone to the extent of holding that a scientific witness can only testify from facts learned by him from personal demonstration. The general rule in such cases, in this state, at least, seems to be that, where a witness exhibits such a degree of knowledge, gained from experiments, observation, standard books, or other reliable source, as to make it appear that his opinion is of some value, he is entitled to testify, leaving to the trial court, in the exercise of a sound discretion, the right to say when such knowledge is shown, and to the jury the right to say what the opinion is worth; and, as in all other cases of discretion, this court will review the action of the trial court only when that discretion clearly appears to have been abused."
Illinois Steel Co. v. Fuller, (1939) 216 Ind. 180, 23 N.E.2d 259, 268. Our review of this expert's qualifications convinces us that clearly there was no abuse of discretion in permitting his testimony. Regarding the state of knowledge in the medical profession at the time, the expert testified that *554"statistics were being published to show the direct relationship of the oral contraceptive pill to an increased disposition in women to develop blood clotting .." The expert then summarized several reports of studies. He was asked, "Was there information in the year 1968 available to the defendant here from these studies, you take the Wright Committee, the British Studies, the Hellman Reports, that did establish a relationship between the use of the pill and thrombophlebitis?" The expert responded "yes." The expert was then requested to read aloud the following portion of Ortho's 1968 Physicians Desk Reference entry for Ortho-Novum: "No comparable studies are yet available in the United States The British data, especially as they indicate the magnitude of the increased risks to the individual patient, cannot be directly applied to women in other countries in which the incidences of spontaneously occurring thromboembolic disease may be different." (Emphasis added). The expert was asked to state his opinion of the adequacy of the warning. After objections, preliminary questions, a recess, and more objections, he stated that in his opinion the warnings were "insufficient, incomplete and misleading." The record further discloses that Ortho employed detail men as a method of communicating with Chapman's doctor, however Chapman's doctor testified that they did no more than leave drug samples and more literature. Ortho in turn offered expert opinion that a causal relationship had not been established between oral contraceptives and thrombophlebitis, and argues that there should be no liability for the failure to state what is not proved true.10 This question of a relationship was properly for the trier of fact to determine. A number of courts have found defendant-manufacturers to be entitled to directed verdicts on the ground that the warnings in question were adequate as a matter of law. See, e. g., Dunkin v. Syntex Laboratories, (W.D.Tenn. 1977) 443 F.Supp. 121; Chambers v. G. D. Searle & Co., (D.Md.1975) 441 F.Supp. 377. We decline Ortho's invitation to follow their example in the case presently before us, notwithstanding the precedent of Carmen v. Eli Lilly & Co., (1941) 109 Ind. App. 76, 32 N.E.2d 729. In Carmen the evidence was without conflict that the warning in question accurately reflected the state of knowledge in the field of medicine regarding the drug in question, and that the plaintiff's doctor had read and understood the warnings. The only expert medical testimony offered with respect to adequacy clearly favored the defendant, thus Carmen is distinguishable from the case at bar. At the very least our research has disclosed that reasonable minds could and have differed with respect to the very language presently at issue. Compare Liebowitz v. Ortho Pharmaceutical Corp., supra, specifically approving this language, with MceEwen v. Ortho Pharmaceutical Corp., supra, characterizing it as "questionable." Clearly we cannot find as a matter of law that the warnings were adequate, nor does Ortho's compliance with federal law require a different result. Gilbert v. Stone City Const. Co., (1976) Ind.App., 857 N.E.2d 788, 745. See also McEwen v. Ortho Pharmaceutical Corp., supra, 528 P.2d at 533-34, and the authority cited therein.
In summary, we find that Chapman offered sufficient evidence on the basis of which the jury could reasonably find Or-tho's warning inadequate, if not, in a technical sense, with regard to factual content, then at least with regard to communicating a clear indication of the risk. This satisfies the element of proof, required of Chapman under § 402A, of a "defective condition unreasonably dangerous." Ortho was properly refused a directed verdict on the basis of this element.
*555b.
Proximate cause is commonly defined as "that cause which, in natural and continuous sequence, unbroken by any efficient intervening cause, produces the result complained of and without which the result would not have occurred." Johnson v. Bender, (1977) Ind.App., 369 N.E.2d 936, 939. This latter language describes what is known as the "but-for" test. A fundamental element of proximate cause is that the injury or consequence of the wrongful act be of a class reasonably foreseeable at the time of that act. Elder v. Fisher, (1966) 247 Ind. 598, 217 N.E2d 847; Meadowlark Farms, Inc. v. Warken, supra. The defendant's act need not be the sole proximate cause; many causes may influence a result. Meadowlark Farms, Inc. v. Warken, supra, 376 N.E.2d at 129. The question is whether "the original wrong was one of the proximate rather than remote causes." Dreibelbis v. Bennett, (1974) 162 Ind.App. 414, 319 N.E.2d 634, 638. Thus, "the ultimate test of legal proximate causation is the reasonable foreseeability. The assertion of an intervening, superceding cause fails to alter this test." Id. Rather,
[WJhere harmful consequences are brought about by intervening independent forces the operation of which might have been reasonably foreseen, then the chain of causation extending from the original wrongful act to the injury is not broken by the intervening and independent forces and the original wrongful act is treated as a proximate cause.
New York Central R. Co. v. Cavinder, (1965) 141 Ind.App. 42, 211 N.E.2d 502, 508. Proximate cause is generally a question for the trier of fact.
A simple "but-for" test of proximate cause is inadequate in the present case for several reasons. First, Ortho-Novum is available only by prescription. Thus the independent actions of a doctor are necessarily a part of causation in fact. Second, an adequate warning with respect to unavoidably unsafe products would not in any way reduce or avoid the risk of harm involved. It would only serve to inform the person to whom the duty to warn extends, in this case the doctor, so that he may choose whether the risk should be incurred at all, or cease use of the product if the risk materializes.11 Finally, Comment j provides a presumption that an adequate warning would be heeded. This operates to the benefit of a manufacturer where adequate warnings in fact are given. Where warnings are inadequate, however, the presumption is in essence a presumption of causation.12
In McEwen v. Ortho Pharmaceutical Corp., supra, 528 P.2d at 588, a case very similar to the case at bar, the problem of causation was analyzed as comprised of two steps. The first question is whether the defendant's failure to adequately warn was a substantial cause of the plaintiff's ingestion of the defendant's oral contraceptive. The second question is whether such ingestion was a substantial cause of the injury suffered. To this we would add that Comment j provides a presumption in the affirmative in response to the first question, which the defendant may rebut.
Ortho has argued four circumstances which preclude a finding that any inadequacy of the warnings was the proximate cause of Chapman's injury. These are, first, that the prescribing doctor had
*556actual knowledge of the risk derived from other sources, second, that the doctor did not rely on Ortho's warnings, third, that Chapman used the drug beyond her pre-seription, and fourth, that Chapman failed to report preliminary symptoms. The first two are essentially the same: the warnings could not have been a substantial cause of the plaintiff's injury if the decision to prescribe was not in any way influenced by the representations therein. Thus, Ortho argues that the evidence shows, as a matter of law, that an adequate warning would not have been heeded in this case. Such an approach is not without precedent. See Douglas v. Bussabarger, (Wash.1968) 438 P.2d 829, and Oppenheimer v. Sterling Drug, Inc., (1964) 7 Ohio App.2d 103, 219 N.E.2d 54. We note, however, that in both cases the prescribing doctor testified that he relied on his own knowledge and experience, and did not read or rely on the defendant's warnings. There is no such evidence in the case at bar. Rather, Chapman's doctor testified that he relied on entries in the P.D.R. as a basis for prescribing drugs. He did not read package inserts as he assumed that they were no different from the P.D.R. entry. His testimony shows that he was "aware" of a study in Britain,13 but not of the specifics, and that had he known, "it would have made a difference." Chapman's doctor testified that at the time he prescribed Ortho's oral contraceptive for Chapman, he believed that it was "completely safe" and that Ortho would have "made sure" he would find out if it were not so. Even if the present case had not been thus distinguishable from Douglas and Oppenheimer, we would not find an absence of proximate cause as a matter of law. The majority of cases have held that the intervening negligence of a doctor does not relieve the manufacturer of liability, provided that the manufacturer's wrongful act may have contributed to it.
See, e. g., McCue v. Norwich Pharmacal Co., (1st Cir.1972) 453 F.2d 1033, 1035 (open-ended renewal of prescription did not relieve manufacturer of liability for inadequate warning that possible side effect of long-term use was pulmonary fibrosis); Sterling Drug, Inc. v. Yarrow, supra, at 994 (doctor's failure to learn of risk from other sources doesn't relieve defendant of liability, and it is foreseeable that doctors do not read all of the literature mailed to them); Sterling Drug, Inc. v. Cornish, supra, at 85 (doctor's allegedly negligent failure to keep abreast of medical literature, including that of defendant's, does not relieve defendant of liability); Stevens v. Parke, Davis & Co., (1973), 9 Cal.3d 51, 107 Cal.Rptr. 45, 507 P.2d 653, 663 (doctor's negligent disregard of warnings given was not intervening cause, since induced by over-promotion of drug). See also Schenebeck v. Sterling Drug, Inc., supra; Hamilton v. Hardy, supra; Krug v. Sterling Drug, Inc., (Mo.S.Ct. 1967) 416 S.W.2d 143; McEwen v. Ortho Pharmaceutical Corp., supra. The concept of warning encompasses more than available printed material.14 The avowed nonreliance present in Douglas and Oppenheimer could have resulted in part from a lack of insistence in endeavoring to attract attention to a warning or a lack of urgency in expressing the substance. In Sterling Drug, Inc. v. Yarrow, supra, this possibility is discussed in the context of reasonableness rather than proximate cause. N evertheless, we feel the reasoning supports our conclusion here. In Yarrow, the defendants argued that they were entitled to reversal because the evidence showed reasonable effort to warn by means of a warning letter mailed to the doctor. The court responded to this argument that:
The "Dear Doctor" letter could have been reasonably found to be lacking in emphasis, timeliness and attention invit*557ing qualities A reasoning mind could find that appellant's warning actions were unduly delayed, reluctant and lacking in a sense of urgency, and therefore unreasonable under the circumstances. While a warning in February 1963 in an attention inviting letter would probably have been timely in this case if promptly received and heeded by appellee's physician, it could be inferred that a reasonably earlier warning, with greater intensity could well have reached appellee's physician directly, or indirectly through other professional channels such as conversations with other doctors and discussions at conventions. The delay in issuance of the "Dear Doctor" letter from August 1962 to February 1963, its wording, and the manner of its circulation could be found unreasonable considering the magnitude of the risk involved. (Emphasis added).
408 F.2d at 994. Where a defendant fails to make reasonable efforts to attract attention to his warning or convey its urgency, a jury could reasonably find the failure to heed such a warning a natural and foreseeable result. The failure to heed a warning may be negligent, but we cannot say as a matter of law that no inadequacy of warning could have contributed to such negligence. Therefore the question of proximate cause should be left for the trier of fact to determine.
The second two contentions of Or-tho concern the actions of the plaintiff. Because Ortho's oral contraceptive is available only by prescription, Ortho's duty to warn is discharged if adequate warnings are given the prescribing and treating doctors. This clearly reflects the assumption that prescription drugs will only be used under some supervision of a doctor. Where a patient evades this supervision, warnings, whether adequate or inadequate, are useless to enable the patient to cease use of the drug if the risk materializes. Thus, in Chambers v. G. D. Searle, supra, wherein the plaintiff did not report her symptoms to her doctor, her doctor had no knowledge of her hypertension and no basis for relating the defendant's warning with respect to hypertension to her case. The court found no proximate cause, as an adequate warning would have made no difference on the doctor's actions. See also, Vaughn v. G. D. Searle & Co., supra, 586 P.2d at 1249-50. In the present case there was evidence that prior to Chapman's manifestation of throm-bophlebitis she had stumbled against a table thereby bruising her leg and causing her to suffer some swelling. Ortho contends that her failure to report this incident precluded a finding of proximate cause. However the evidence was conflicting as to whether the incident was in fact a symptom or indication of thrombophlebitis, therefore the question was properly presented to the jury for resolution.
By the same reasoning, use without or beyond a prescription could preclude a finding of proximate cause. Chapman's prescription was for one year. Her doctor's records indicated that he gave her the prescription on July 21, 1968. Chapman testified that she used the pill from November, 1968, to January, 1970, when her thrombo-phlebitic episode occurred. Thus it is not clear how long over one year she continued to have the prescription filled, but it was certainly no longer than six months. Her expert testified that it made no difference whether she began use of the pill in July or November of 1968, with regard to causation. In Oppenheimer v. Sterling Drug, Inc., supra, the prescription in question was refilled for two and a half years, although it was supposed to be limited to six months. In addition, the plaintiff was out of touch with her physician for a period of a year and three months. The court affirmed the grant of a directed verdict on the ground that reasonable minds could only conclude that the doctor's nonreliance on the warnings, the druggist's unauthorized filling of the prescription and the plaintiff's own actions constituted the cause of her injuries. Comparing the above decision with that in McCue v. Norwich Pharmacal Co., supra, concerning an open-ended prescription, we are persuaded that a directed verdict may not always be appropriate in the cireum-stances discussed above. The essential
*558question is whether the inadequacy of the warnings was a substantial factor in bringing about the harm. It is not unreasonable to suggest that had the doctor been adequately warned he in turn would have impressed on the patient the importance of medical supervision. In the present case it could be supposed that Chapman might then have regarded with more suspicion that which could be viewed as a relatively trivial accident (assuming here that her bruise was indeed a symptom). It is possible that some inadequacy of warning thus contributed to the actions of either doctor or patient, and that those actions may have been reasonably foreseeable. We do not disagree that the actions of a doctor or his patient may be efficient intervening causes, but it is for the trier of fact to make such a determination in this case. See New York Central R. Co. v. Cavinder, supra, 211 N:E.2d at 508-09.
The second question in determining proximate cause is whether ingestion of Ortho's oral contraceptive caused Chapman's thrombophlebitis. Ortho's brief on appeal does not challenge the jury's finding in the affirmative in this case, therefore we do not address this question except to note that «Chapman presented expert testimony in support of this finding.
We conclude that the trial court did not commit error in overruling Ortho's motion for judgment on the evidence.
II.
Because of our disposition of this case, it is unnecessary to deal with the issues raised by Ortho respecting the trial court's instructions given to the jury.
II.
Ortho contends that the trial court erred in admitting certain exhibits, those being a Federal Drug Administration-mandated "Patient Warning" from August, 1970, an Ortho-Novum 2 mg. package insert from January, 1970, and an advertisement of Or-tho's oral contraceptive in a J anuary 15, 1970 magazine directed primarily to obstet-
ricians and gynecologists, which Chapman's doctor never saw. Ortho argues that the admission of post-occurrence remedial measures taken by a defendant to show negligence is contrary to the law in Indiana, citing Terre Haute & Indianapolis RR. v. Clem, (1890) 123 Ind. 15, 23 N.E. 965, and Dudley Sports Co. v. Schmitt, (1972) 151 Ind.App. 217, 279 N.E.2d 266.
As we noted earlier, the knowledge chargeable to a manufacturer is limited to what was known at the time the plaintiff was taking the drug in question. Basko v. Sterling Drug, Inc., supra, at 426. The duty to warn continues throughout this period. Schenebeck v. Sterling Drug, Inc., supra. Chapman used Ortho's oral contraceptive until after her emergency surgery on January 15, 1970, when she discontinued it at the urging of the doctor who performed the operation. Therefore we do not see how an advertisement in a magazine dated January 15, 1970, can be characterized as a post -occurrence remedial measure.
The Patient Warning is clearly another matter, however. The trial court admitted this exhibit for the limited purpose of showing examples of the kind of caution which could have been given, and not as evidence of negligence on the part of Ortho. Chapman urges the correctness of the trial court's action both on the ground relied on by that court, and on the ground that the rule excluding evidence of post-accident remedial measures is not applicable in actions under section 402A of the Restatement of Torts.
The "caution" exception relied on by the trial court relates to the feasibility of taking certain precautions being proved by a showing that such precautions were in fact subsequently taken. It must be noted that this exception is a development of the exception permitting evidence of subsequent remedial measures for rebuttal or impeachment purposes. See, e. g. Hickey v. Kansas City Southern R. Co., (Mo.1956) 290 S.W.2d 58 (evidence of subsequent precautions admissible to rebut contention that conditions
*559could not be made safer); American Airlines Inc. v. United States, (5th Cir.1969) 418 F.2d 180 (evidence of subsequent precautions not admissible to show antecedent negligence but may be used for rebuttal or impeachment); Hyndman v. Penn. R. R. Co., (1959) 396 Pa. 190, 152 A.2d 251 (evidence of post-accident posting of warning sign admissible to rebut defendant's contention that the cost of doing so was excessive in view of the risk); Grawey v. Board of Road Com'rs., (1973) 48 Mich.App. 742, 211 N.W.2d 68 (evidence that road repaired after accident would have been admissible in rebuttal if commissioners had defended on ground of insufficient funds to make repairs; however, plaintiff not permitted to anticipate defense). Thus, the traditional rule as embodied in the Federal Rules of Evidence allows evidence of subsequent measures to be admitted, "when offered for another purpose, such as proving ownership, control, or feasibility of precautionary measures, if controverted, or impeachment." (emphasis added). The Advisory Committee's Note adds:
The requirement that the other purpose be controverted calls for automatic exclusion unless a genuine issue be present and allows the opposing party to lay the groundwork for exclusion by making an admission. Otherwise the factors of undue prejudice, confusion of issues, misleading the jury, and waste of time remain for consideration under Rule 408.
There is some case law to the contrary, particularly Brown v. Quick Mix Co., (1969) 75 Wash.2d 833, 454 P.2d 205, 210, wherein the court expressly held such evidence "competent regardless of whether the issue is part of the plaintiff's case . . or [whether] the defendant inject[ed] 1t as a defense." We feel the more accurate understanding of the law was demonstrated by the dissenting judge, who stated that to allow the plaintiff to raise the feasibility issue lets the jury find the defendant negligent "on evidence admitted on an issue which it neither created nor contested." The danger in permitting this is discussed in 2 J. Weinstein & M. Berger, Weinstein's Evidence-United States Rules, 407-14 to -15:
[T]his exception is troublesome because the feasibility of a precaution may bear on whether it was negligent not to have taken the precaution; thus, negligence and feasibility are often not distant issues. There is no difficulty when the defendants open up the issue by claiming that further precautionary measures were not practicable or feasible. By raising the issue of feasibility defendant in effect has waived the protection of Rule 407 [which generally bars the admission of subsequent remedial measures], for it would be unfair not to allow the plaintiff to meet the issue by showing defendant's conflicting conduct-the subsequent remedial measures.
Allowing a plaintiff to raise feasibility would incapacitate the general rule. See 2 Weinstein's Evidence, supra, I 407[01], at p. 407-6, n. 7, and authorities cited therein.
Chapman cites Lolie v. Ohio Brass Co., (7th Cir. 1974) 502 F.2d 741, as adopting this "caution" exception. That case, however, concerned strict liability for the defective design of metal clips holding a cable to the roof of a mine. The cable fell and a miner was killed. After the accident, a State mine inspector directed the mine operator to tie the cable in place every sixty feet to give additional support. The court held that the exclusion of this subsequent precaution from evidence was not reversible error, although it should have been admitted. The court stated that in a defective design case, a plaintiff must prove that the product as designed is incapable of preventing the injury complained of, that there is an alternate design which would have prevented the injury, and that the alternative design is feasible. 502 F.2d at 744. The admissibility of evidence of subsequent precautions in this kind of case is not irreconcilable with the general exclusionary rule and its exceptions embodied in Rule 407. Feasibility is in issue by reason of the na*560ture of the case,15 and the defendant has the opportunity to concede the issue.16
The present case is not at all similar. There is no need for the plaintiff to prove the defendant's practical ability to print warnings. The defendant never claimed it could not. If the evidence was offered to show an example of a reasonable mode of conveying a warning, it is irrelevant because there was as a matter of law no duty to directly warn the patient during the time in question. If the purpose of showing a caution which could have been made referred to the content, then it clearly was an attempt to prove that "because the world grows wiser as it gets older, therefore it was foolish before." Columbia & P. S. R. Co. v. Hawthorne, (1892) 144 U.S. 202, 12 S.Ct. 591, 36 L.Ed. 405 quoting Hart v. Railway, 21 Law T. (N.S.) 261, 263. This is exactly what the exclusionary rule pro— scribes.
As its second ground for the admissibility of this evidence, Chapman relies on Ault v. International Harvester Co., (1975) 13 Cal.3d 113, 117 Cal.Rptr. 812, 528 P.2d 1148, for the proposition that the exclusionary rule is inapplicable in strict liability cases. The reasoning of that case is, in essence, that the rule relates to proof of negligence, the reasonableness of the defendant's conduct, whereas strict liability theory is concerned only with product defects regardless of negligence. In addition, it is reasoned that the policy underlying the rule loses force where "contemporary corporate mass producer{s]" are concerned, therefore the rule operates only as,. a shield to liability.
The first argument is beside the point. The defect attributable to the product in this case is not in the design or manufacture of the drug, but in the failure to adequately warn of the dangers in its use. Thus, inquiry must focus on the conduct of the defendant:
[WJhere the duty to warn is under consideration, the standard of strict liability is essentially similar to the standard for establishing negligence. The rule imposing obligation on the manufacturer or seller to give suitable warning. .of a dangerous propensity of an article produced or sold, and the rule conditioning liability on the fact of knowledge or reason to acquire knowledge of a dangerous propensity, are the rules fixing the duties of care and are part of the law of negligence.
72 CJ.S. Products Liability § 25 (1978 Supp.).
More on point than Ault, supra, is Smith v. E. R. Squibb & Sons, Inc., supra, which involved a wrongful death action, based on negligence and implied warranty theories, for failure to adequately warn of dangers associated with the use of an x-ray contrast medium produced by the defendant. With regard to the evidence question the court held:
Defendant argues, however, that even if the proposed exhibits were inadmissible to prove negligence, they should have been admitted under plaintiff's implied warranty count to prove the product was defective. We disagree. Inasmuch as the plaintiff's entire case was built around proof of an inadequate warning, a negligence concept, the theoretical distinction between negligence and implied warranty may not be exploited to obviate the policy reasons for the exclusionary rule.
245 N.W.2d at 58. We agree completely, and find the trial court erred.
Finally, the policy argument in Ault requires some response here. The court in Ault reasoned:
Nevertheless, courts and legislatures have frequently retained the exclusionary rule in negligence cases as a matter of *561"public policy," reasoning that the exclusion of such evidence may be necessary to avoid deterring individuals from making improvements or repairs after an accident has occurred.
When the context is transformed from a typical negligence setting to the modern products liability field, however, the "public policy" assumptions justifying this evidentiary rule are no longer valid. The contemporary corporate mass producer of goods, the normal products liability defendant, manufactures tens of thousands of units of goods; it is manifestly unrealistic to suggest that such a producer will forego making improvements in its product, and risk innumerable additional lawsuits and the attendant adverse effect upon its public image, simply because evidence of adoption of such improvement may be admitted in an action founded on strict liability for recovery on an injury that preceded the improvement. In the products liability area, the exclusionary rule of section 1151 does not affect the primary conduct of the mass producer of goods, but serves merely as a shield against potential liability. In short, the purpose of section 1151 is not applicable to a strict liability case and hence its exclusionary rule should not be gratuitously extended to that field.
528 P.2d at 1151-52.
The rule excluding evidence of post-accident repairs or precautions was first established by the United States Supreme Court in Columbia & P. S. R. Co. v. Hawthorne, supra. That case concerned a suit for personal injuries caused by a defective machine. The Court ruled that evidence of subsequent alterations or repair of the machinery was incompetent on three grounds:
[The taking of such precautions against the future is not to be construed as an admission of responsibility for the past, has no legitimate tendency to prove that the defendant had been negligent before the accident happened, and is calculated to distract the minds of the jury from the real issue, and to create a prejudice against the defendant.
144 U.S. at 207; 12 S.Ct. at 598. The Court approved the reasoning expressed in Morse v. Railway Co., (1888) 30 Minn. 465, 16 N.W.
[SJuch acts afforded no legitimate basis for construing such an act as an admission of previous neglect of duty. A person may have exercised all the care which the law required, and yet in the light of his new experience, after an unexpected accident has occurred, and as a measure of extreme caution, he may adopt additional safeguards. The more careful a person is, the more regard he has for the lives of others, the more likely he would be to do so; and it would seem unjust that he could not do so without being liable to have such acts construed as an admission of prior negligence. We think such a rule puts an unfair interpretation upon human conduct, and virtually holds out an inducement for continued negligence. (Emphasis added).
Also the Court quoted Hart v. Railway, 21 Law T. (N.S.) 261, 263, as stating the same rule:
People do not furnish evidence against themselves simply by adopting a new plan in order to prevent the recurrence of an accident. I think that a proposition to the contrary would be barbarous. It would be, as I have often had occasion to tell juries, to hold that, because the world gets wiser as it gets older, therefore it was foolish before.
Although courts have emphasized the public policy considerations in applying the rule, these considerations are not its keystone. Rather, lack of probative value is the fundamental reason for excluding such evidence. Although such evidence may be admissible under the modern, more liberal test of relevance, the attendant danger that a jury would misconstrue and misapply it to the prejudice of the accused is so great as to require exclusion. 2 J. Wigmore, Evidence § 283 (3d ed. 1940). A danger particularly relevant to the present case is that a jury, influenced by hindsight evidence, might apply an artificially high standard in determining the adequacy of warnings. With respect to this issue, the Indiana Supreme
*562Court in Terre Haute & I. R. Co. v. Clem, supra, quoted from Nalley v. Carpet Co., 51 Conn. 524: ~
The fact that an accident has happened, and a person has been injured, immediately puts a party on a higher plane of diligence and duty, from which he acts with a view of preventing the possibility of a similar accident, which should operate to commend rather than condemn the person so acting. If the subsequent act is made to reflect back upon the prior one, although it is done upon the theory that it is a mere ddmission, yet it virtually introduces into the transaction a new element and test of negligence, which has no business there, not being in existence at the time.
Even "contemporary corporate mass producer[s]" are entitled to be judged by a fair standard.
The evidence in this case presented the jury with a very close question regarding the adequacy of Ortho's warnings. Therefore we cannot say the error in admitting this evidence was harmless.
We reverse, and remand this cause for new trial.
HOFFMAN, J., concurs. LOWDERMILK, J., dissents with opinion.. Section 402A states:
Special Liability of Seller of Product for Physical Harm to User or Consumer (1) One who sells any product in a defective condition unreasonably dangerous to the user or consumer or to his property is subject *545to liability for physical harm thereby caused to the ultimate user or consumer, or to his property, if
(a) the seller is engaged in the business of selling such a product, and
(b) it is expected to and does reach the user or consumer without substantial change in the condition in which it is sold.
(2) The rule stated in Subsection (1) applies although
(a) the seller has exercised all possible care in the preparation and sale of his product, and
(b) the user or consumer has not bought the product from or entered into any contractual relation with the seller.
. See Wade, Strict Tort Liability of Manufacturers, 19 S.W.L.J. 5, 14-15 (1965):
The more difficult problem arises with a product which was made in the way it was intended to be made and in the condition planned and which yet proves to be dangerous. Is such an article defective? * * * In cases of this general type the phrase "defective condition" has no independent meaning, and the attempt to use it is apt to prove misleading. The only real problem is whether the product is "unreasonably dangerous," because "defective condition," if it is to be applied at all, depends on that.
Other commentators have suggested that the lack of adequate warning is what renders the product "defective." See 2 L. Frumer & M. Friedman, Products Liability § 16A[4l[e] (1967).
. There are three reasons for which a drug may be deemed "ethical," or available only by prescription: it may be habit-forming; it may be unsafe for use except under a doctor's supervision due to its toxic quality, its potential for harmful effect, or method of use; and its availability may be limited by the terms of Federal Drug Administration approval. 21 U.S.C. § 353(b)(1) (1970).
. See Lawson v. G. D. Searle & Co., (1976) 64 II1.2d 543, 547, 1 IIl.Dec. 497, 501, 356 N.E.2d 779, at 783.
. Comment j provides:
J. Directions or warning. In order to prevent the product from being unreasonably dangerous, the seller may be required to give directions or warning, on the container, as to its use. The seller may reasonably assume that those with common allergies, as for example to eggs or strawberries, will be aware of them, and he is not required to warn against them. Where, however, the product contains an ingredient to which a substantial number of the population are allergic, and the ingredient is one whose danger is not generally known, or if known is one which the consumer would reasonably not expect to find in the product, the seller is required to give warning against it, if he has knowledge, or by the application of reasonable, developed human skill and foresight should have knowledge, of the presence of the ingredient and the danger. Likewise in the case of
poisonous drugs, or those unduly dangerous for other reasons, warning as to use may be required.
But a seller is not required to warn with respect to products, or ingredients in them, which are only dangerous, or potentially so, when consumed in. excessive quantity, or over a long period of time, when the danger, is generally known and recognized. Again, the dangers of alcoholic beverages are an example, as are also those of foods containing such substances as saturated fats, which may over a period of time have a deleterious effect upon the human heart.
Where warning is given, the seller may reasonably assume that it will be read and heeded; and a product bearing such a warning, which is safe for use if it is followed, is not in defective condition, nor is it unreasonably dangerous.
See Davis v. Wyeth Laboratories, Inc., infra, and O'Hare v. Merck & Co., (8th Cir.1967) 381 F.2d 286, 291.
. There is some argument against applying this rule with respect to drugs such as oral contraceptives, see Comment, Liability of Birth Control Pill Manufacturers, 23 Hastings L.J. 1526 (1972), which is effectively answered in Terhune v. A. H. Robins Co., (1978) 90 Wash.2d 9, 577 P.2d 975, 978. We note that after the appellee ceased taking Ortho-Novum, the Federal Drug Administration issued a regulation requiring that warnings be directed to patients in the case of oral contraceptives. See 21 C.F.R. 310.501(a) (April 1, 1977). However, we will not impose this expansion of duty retrospectively.
. Section 388 states:
Chattel Known to be Dangerous for Intended Use
One who supplies directly or through a third person a chattel for another to use is subject to liability to those whom the supplier should expect to use the chattel with the consent of the other or to be endangered by its probable use, for physical harm caused by the use of the chattel in the manner for which and by a person for whose use it is supplied, if the supplier
(a) knows or has reason to know that the chattel is or is likely to be dangerous for the use for which it is supplied, and
(b) has no reason to believe that those for whose use the chattel is supplied will realize its dangerous condition, and
(c) fails to exercise reasonable care to inform them of its dangerous condition or of the facts which make it likely to be dangerous.
This section has recently been adopted as the law of Indiana, in Stapinski v. Walsh Construction Co., (1978) Ind.App., 303 N.E.2d 473.
. The issue of defenses in particular may require that instructions be limited to one theory. For instance, a jury's finding of no liability in negligence by reason of the plaintiff's contributory negligence is only of theoretical interest where strict liability under § 402A has been alleged as well. Liability for the latter could be based on the same findings of fact as nonliability for the former, since contributory negligence is not a defense to strict liability under § 402A. Perfection Paint & Color Co. v. Konduris, (1970) 147 Ind.App. 106, 258 N.E.2d 681, 689. Thus there may be no need to instruct the jury with respect to the negligence count.
. The June, 1968 package insert and the 1969 Physicians' Desk Reference contained the following language, which conformed to the Federal Food and Drug Administration's requirement for uniform labeling of package inserts for oral contraceptives:
"WARNINGS 1. The physician should be alert to the earliest manifestations of thrombotic disorders (thrombophlebitis, cerebro-vascular disorders, pulmonary embolism, and retinal thrombosis). Should any of these occur or be suspected, the drug should be discontinued immediately. Studies conducted in Great Britain and reported in April 1968 estimate there is a seven to tenfold increase in mortality and morbidity due to thromboembolic diseases in women taking oral contraceptives. In these controlled retrospective studies, involving 36 reported deaths and 58 hospitalizations due to 'idiopathic' thromboembolism, statistical evaluation indicates that the differences observed between users and non-users were highly significant. The conclusions reached in the studies are summarized in the table below:
Comparison of Mortality and Hospitalization Rates Due to Thromboembolic Disease in Users and NonUsers of Oral Contraceptives in Britain Hospitalization Rates Category Morbidity Age 20-34 Age 35-44 Age 20-44 Users of Oral Contraceptives 1.5/100,000 3.9/100,000 47/100,000 Non-Users 0.2/100,000 0.5/100,000 5,100,000 No comparable studies are yet available in the United States. The British data, especially as they indicate the magnitude of the increased risk to the individual patient, cannot be directly applied to women in other countries in which the incidences of spontaneously occurring thromboembolic disease may be different. * * # # # * ADVERSE REACTIONS OBSERVED IN PATIENTS RECEIVING ORAL CONTRACEPTIVES A statistically significant association has been demonstrated between use of oral contracep*554tives and the following serious adverse reactions: Thrombophlebitis Pulmonary embolism."
. With respect to this argument we note the following language from Hamilton v. Hardy, supra, at 1108, citing McCue v. Norwich Phar-macal Co., infra, as authority: "In this connection, we would also point out that, under a strict liability theory, a manufacturer must warn of dangers and risks, whether or not a causal relationship between use of the product and the various injuries has been definitely established at the time of the warning." (Emphasis added).
. See Hamilton v. Hardy, supra, 549 P.2d at 1110; "The warning thus achieves two purposes: (1) It will alert the doctor to premonitory symptoms of the side effect. Reyes, supra; Vaughn v. G. D. Searle & Co., supra; and (2) it will enable the patient to evaluate the relative advantages and disadvantages of taking the drug. See McEwen, supra." -
. See Comment j, supra, and Technical Chemical Co. v. Jacobs, (Tex.1972) 480 S.W.2d 602, 606: Such a presumption works in favor of the manufacturer when an adequate warning is present. Where there is no warning, as in this case, however, the presumption that the user would have read an adequate warning works in favor of the plaintiff user. In other words, the presumption is that Jacobs would have read an adequate warning. The presumption, may, however, be rebutted if the manufacturer comes forward with contrary evidence that the presumed fact did not exist.
. According to the record, there were three studies in Great Britain during 1965 and 1966 to determine whether a cause-and-effect relationship existed between the use of oral contraceptives and thrombosis, thromboembolism, and other vascular diseases, published in Ves-sey & Doll, 2 British Medical J. 199 (1968).
. See Merrill, Compensation for Prescription Drug Injuries, supra at 23, for a thorough discussion of ineffective drug labelling.
. In Hoppe v. Mzdwest Conveyor Co. (8th Cir. 1973) 485 F.2d 1196, 1202, another defective design case, the court stated that evidence of © post-accident design modifications is admissible because such a case "encompasses many factors not generally relevant to ordinary negligence in tort cases."
. See Haysom v. Coleman Lantern Co., Inc., (Wash.1978) 573 P.2d 785, 791. However the court refused to adopt a rule of "universal admissibility of post-injury changes," although defective design was in issue.