dissenting.
I respectfully dissent..
I.
In Keener v. Dayton Electric Manufacturing Company, 445 S.W.2d 362 (Mo.1969) our Supreme Court adopted 2 Restatement, Law of Torts, Second, Sec. 402A dealing with strict liability for products. The court identified three bases for the adoption of that section. The first was a policy matter identified in Greenman v. Yuba Power Products, Inc., 59 Cal.2d 57, 27 Cal.Rptr. 697, 377 P.2d 897, 13 A.L.R.3d 1049 (1963) [4] as “the purpose of such liability is to insure that the cost of injuries resulting from defective products are borne *405by the manufacturers [and sellers] that put such products on the market rather than by the injured persons who are powerless to protect themselves.” The second basis was to free such litigation from the “shackles of warranty language” and the third was to give some sense of direction in products liability cases. Whether the third basis has been effectively achieved might be questioned.
Section 402A includes a series of comments explaining the origin, extent and application of the section. Comments a, b, and c essentially deal with the placement of the section, its history, and the policy reasons behind it, the last closely paralleling the first basis advanced in Keener. Comments d and e identify the types of products to which the section pertains. Comment f identifies the persons or entities upon whom the liability is imposed. Comments g, h and i define the scope and meaning of “defective condition” and “unreasonably dangerous”. Comment i contains the language “Many products cannot possibly be made entirely safe for all consumption, and any food or drug necessarily involves some risk of harm, if only from overconsumption.” (Emphasis supplied). Comments j and k then establish the requirements to be followed for those products which cannot be made entirely safe. Comment j creates the basis for what is commonly referred to as “failure to warn product liability cases” and verdict-director MAI 3d 25.05. Comment k deals with unavoidably unsafe products and states that “such a product if properly prepared, and accompanied by proper directions and warning, is not defective, nor is it unreasonably dangerous.” (Emphasis in original).
In Racer v. Utterman, 629 S.W.2d 387 (Mo.App.1981) we dealt with a surgical drape having inflammatory qualities. We rejected in that case a requirement that the jury be instructed on the defendant’s knowledge of the dangerous condition. We premised that conclusion on the basic concept of products liability that the fault or negligence of the defendant is simply not relevant. We declined to apply the defensive warning language of comment j for two reasons. Initially we held that comment j as pertains to defendant’s knowledge of the danger is limited to “those products which are either ingested or placed in contact with the body and where the injury results from the interaction of the product (or an ingredient of the product) with the body itself.” Secondly we held the defensive warning language went beyond mere constructive knowledge to a level approaching, if not reaching, impossibility of knowledge. Neither situation applied to the drape in question nor the injuries resulting to plaintiff from its inflammability. As to the first basis we specifically reserved opinion on the applicability of the absence of knowledge of the manufacturer on his duty to warn in the case of drugs. The issue reserved in that case has not been subsequently resolved in Missouri.
II.
As indicated, comment k deals with products delineated as unavoidably unsafe. It speaks particularly to drugs. Comment k, as heretofore indicated, states that an unavoidably unsafe product properly prepared and accompanied by proper directions and warning is not defective nor unreasonably dangerous. I can view comment k as nothing other than a statement of policy placing those types of products into a different treatment situation than other products. Comment j obviates the need of a warning (where knowledge, actual or constructive, is absent) only to those products where the danger is the result of interaction between the product and the human body itself. This is a reasonable approach. The vagaries of human reaction to products or ingredients contacting, or being ingested into, the human body are almost infinite. Such reactions are frequently indeterminable for many years or may arise because of unique susceptibility by such a limited portion of human beings that causal connection may be difficult to establish.
It is my belief that comment k and comment j were intended to afford a special protection to drug products and in so doing to inject into products liability cases involving prescription drugs a limited aspect of *406negligence concepts. In that regard I am in agreement with the extensive and carefully crafted opinion in Brown v. Superior Court (Abbott Laboratories), 44 Cal.3d 1049, 245 Cal.Rptr. 412, 751 P.2d 470 (1988). It should be noted that that opinion, holding all prescription drugs to be covered by comment k, was unanimously decided by the same court that originally established the concept of strict product liability in Greenman v. Yuba Power Products, Inc., supra. Comment k therefore provides freedom from liability to prescription drugs where they are properly prepared and adequate warnings are given. Such products are not under those circumstances defective or unreasonably dangerous. Comment j excuses warnings for such products if the manufacturer has no knowledge of the danger and by the application of reasonable, developed human skill and foresight could not have such knowledge.
In my opinion that protection extends to all prescription drugs and is not, as the majority holds, determined on a case by case basis. In that regard I find the reasoning in Brown, supra, persuasive. Unlike the majority I am unable to read the language of comment k as evidencing a case by case approach. The comments to the Restatement are obviously not statutes and there is considerable doubt that their interpretation should follow the more rigid requirements of statutory interpretation. They are simply explanations and expression of policy of the purpose and intent of the Restatement sections.
My interpretation of comment k is that it identifies a generic group of products entitled to comment k protection. Specifically those products include drugs and other unknown or unidentified products meeting comment k standards. Comment i specifically states that all drugs necessarily involve some risk of harm. The references to “many” in comment k refer to the many drugs to which a known risk attaches and distinguishes those from drugs having no known risk or which have been determined to be safe, if such a determination can ever be definitively made.1 It does not refer to the question of the efficacy or value of the drug. This is evident by the reference in comment k to “many of which for this very reason [inherent potential of harm] cannot legally be sold except to physicians, or under the prescription of a physician.” Clearly that language is directed to risk, not to the overall value of the drug. The same is true of the reference to new and experimental drugs.
Prescription drugs, almost by definition, possess the potential of risk to some patient under some circumstances. Drugs must be dispensed by prescription if they (1) are habit forming, or (2) because of toxicity or other potential for harmful effect are not safe for use except under supervision of a medical practitioner, or (3) are new. 21 U.S.C.A. Sec. 353(b)(1). New drugs can be authorized for prescription dispensing if they have tested out to be effective and safe for use under the conditions prescribed, recommended or suggested in the proposed labeling. 21 U.S.C.A. Sec. 355(d). The evaluation and balancing of efficacy and safety is vested with the Federal Drug Administration. I question the authority of a court, applying the case by case approach upheld by the majority, to evaluate that balance between efficacy and safety or between safety and usefulness. United States v. Articles of Drug-Hormonin, 498 F.Supp. 424 (D.C.N.J.1980) [1-6].
Further, prescription drugs are to be utilized by trained medical professionals for treatment of patients’ medical problems. Under concepts of informed consent the patient is presumably advised of the identified dangers from the drug and in consultation with his physician makes the balancing determination between benefits and danger. To apply a case by case analysis to the applicability of comment k to prescription drugs is to place a court in a position of second-guessing the FDA, the physician and the patient. As a matter of both policy and authority I am unable to conclude that courts should engage in such a balancing test. As to all prescription drugs I would hold that comment k applies and that an *407element of plaintiff’s proof is that the manufacturer failed to warn of a danger actually or constructively known. It is also apparent that the balancing test is impossible if the potential danger is unknown and incapable of determination. If only the benefit is known there is nothing to balance except the possibility of some unknown danger of unknown seriousness. The purpose of comments j and k is to protect the drug manufacturer from liability for such unknowns.
III.
I further am in disagreement with the majority that absence of knowledge is an affirmative defense. Comment k specifically states that unavoidably unsafe products properly prepared and accompanied by proper directions and warning are neither defective nor unreasonably dangerous. Sec. 402A liability is premised upon a defective product unreasonably dangerous to the user or consumer. If the product is neither then liability does not exist. Comment k authorizes, without liability, distribution of prescription drugs properly prepared and accompanied by proper directions and warnings. Under comment j warning is only required of dangers which are actually or constructively known. Comment k, therefore, as to prescription drugs injects negligence concepts into product liability claims involving those products. Brown v. Superior Court (Abbott Laboratories), surpa, [1]. An essential element of plaintiffs burden is to establish a failure to warn of a danger known actually or constructively.2 Failure to establish that element is fatal in a failure to warn case involving prescription drugs. I would have no difficulty in holding that a plaintiff makes a prima facie case upon proof of the absence of a warning of a danger in the drug thereby shifting the burden of going forward to the defendant. Just as in res ipsa loquitur and rear-end collision cases such shifting does not, however, change the ultimate burden of proof from plaintiff to defendant. McCloskey v. Koplar, 329 Mo. 527, 46 S.W.2d 557 (banc 1932) [3, 6]; Barlow v. Thornhill, 537 S.W.2d 412 (Mo. banc 1976) [7, 8]. Such shifting of the burden of going forward does not convert an essential element of plaintiff’s case into an affirmative defense. An affirmative defense is “matter constituting a defense; new matter which assuming the complaint to be true, constitutes a defense to it.” Black’s Law Dictionary, 5th Ed. Comment k by premising defendant’s liability on negligence concepts requires that plaintiff bear the ultimate burden of establishing defendant’s knowledge of the dangerous condition about which it failed to warn. I do not regard comment k as an affirmative defense.3
IV.
Even assuming the majority opinion is correct on the first two issues (case by case approach and affirmative defense) I have great difficulty concluding that defendant waived the issue of its knowledge of the danger. In their second amended petition plaintiffs stated, in connection with an allegation supporting punitive damages, that defendant knew of the danger of which it failed to warn. Defendant denied that allegation. The issue of defendant’s knowledge of a danger greater than that of which it warned was litigated throughout the trial.
No case in this state had ever determined the applicability of comment k to prescription drugs and whether comment k constitutes an affirmative defense. Plaintiffs made no assertion in their brief here that the matter had been waived. Their only *408reference to the subject of affirmative defense was that by enactment of Secs. 537.-760 through 537.764 the general assembly had established “state of the art” as an affirmative defense in failure to warn cases. This purportedly established the public policy of the state and this purportedly affirmed that prior to enactment of the statute no duty existed on plaintiff’s part to establish defendant’s knowledge of the danger. The statute in question did not become effective until shortly before trial and considerably after the plaintiff’s injury and all the pleadings had been filed. The statute legislatively overruled the decision of Elmore v. Owens-Illinois, Inc., 673 S.W.2d 434 (Mo. banc 1984). Elmore did not involve a comment k product. The statute has created an affirmative state of the art defense as to non-comment k products. Comment k combined with comment j have always contemplated a knowledge requirement as an element of a case involving a prescription drug.4 I am unable to glean from the statute or from the prior case law in this state any basis for defendant to anticipate that invocation of comment k required an affirmative defense.
Racer, supra indicated that comment j combined with comment k might cover a prescription drug case and gives no indication that they must be raised as an affirmative defense. In Nesselrode v. Executive Beechcraft, Inc., 707 S.W.2d 371 (Mo. banc 1986) two judges observed the difference between usual products liability cases and drug cases as to the question of the manufacturer’s knowledge, l.c. 389 (Blackmar concurring) l.c. 394 (Welliver dissenting). The language of comment k can reasonably be interpreted as making defendant’s knowledge of the danger to be warned against an essential element of the plaintiff's case. The pleadings placed the matter at issue. The case was tried at least in part on the issue of defendant’s knowledge. The majority opinion acknowledges that the defendant’s knowledge was a relevant issue in the case unless waived. Under those circumstances I find it unfair to affirm this large judgment on the basis of a waiver of what the majority acknowledges is a relevant issue.
V.
I am also in disagreement with the majority conclusion concerning Dr. Sussman’s. testimony involving danger from injection into the nerve root dural sleeve. The warning on the package insert stated: “The drug is extremely toxic when injected intra-thecally in animals. Therefore great caution must be exercised in assuring that chyrodiactine is not injected intrathecally into the dural canal.” This warning was repeated a second time with specific reference to the dural canal in the human. Dr. Sussman and other experts were agreed that the drug entered the dural canal because the doctor injecting the drug pierced the spinal column dural sleeve. Dr. Suss-man testified that the drug could also enter the spinal fluid if the physician pierced the nerve root dural sleeve. This he testified did not happen. He then, however, premised his opinion upon the dangerousness of the drug and the inadequacy of the warnings upon the difficulty of avoiding the nerve root dural sleeve. Dr. Sussman testified by deposition. His testimony concerning the nerve root dural sleeve was objected to and the objection was overruled with a court-granted continuing objection to testimony concerning the nerve root dural sleeve.
As an explanation of one of two ways in which the drug could contaminate the spinal fluid I have no objection to Dr. Suss-man’s testimony. But when he was then allowed to testify that it was the potential of nerve root dural sleeve puncture that rendered the drug dangerous and the warnings inadequate his testimony became irrelevant and objectionable.
The danger hypothesized by Dr. Suss-man was totally unrelated to the injury suffered by plaintiff. Plaintiff was not injured because the nerve root dural sleeve was pierced. Had that potential been the subject of warning plaintiff would still *409have sustained his injury. While the requirements of proximate cause have been relaxed (Jackson v. Ray Kruse Construction Company, Inc., 708 S.W.2d 664 (Mo. banc 1986)) I am not aware that they have been totally eliminated. There must still be a correlation between the danger and the plaintiffs injury. Myers v. Bi-State Development Agency, 567 S.W.2d 638 (Mo. banc 1979) [5, 6]; Butcher v. Main, 426 S.W.2d 356 (Mo.1968) [3, 4], It does not do to contend, as the majority does, that once a drug has been identified as being dangerous that any and all injuries arising from use of that drug are compensable, whether arising from that danger or not. Unless the danger is related to the injury the evidence of the danger is irrelevant and should not be admitted. In this case I cannot conclude that the admission of this testimony was harmless.
VI.
I find it unnecessary to discuss at length other issues involved on the appeal. I will comment that the discussion in the majority opinion concerning post-injury remedial measures is premised upon the majority’s conclusion that this is not a negligence action. To the degree that comment k injects into prescription drug product liability cases the element of defendant’s knowledge, and therefore negligence, the majority conclusion fails. In that posture DeLuryea v. Winthrop Laboratories, 697 F.2d 222 (8 Cir.1983) is persuasive. As previously stated Racer v. Utterman, supra did not reject negligence concepts in a prescription drug case. It specifically reserved that question. It does not therefore preclude the application of DeLuryea.
VII.
I note in passing that I find it most unusual that in a case based upon an inadequate warning the court would refuse the jury’s request to examine the actual instructions and warning, three and one half pages in length.
VIII.
Despite our understandable desire to compensate persons for injuries they have incurred through no fault of their own, it is also important that we recognize the social consequences of our decisions on the public generally. We do not benefit that public by making beneficial products, particularly prescription drugs designed to provide relief or cure from disease and suffering, economically unavailable because of possible unknown risks and subsequent large liability awards. Our holding herein does not, in my opinion, uphold public policy. I do not believe this defendant has received a fair trial. I would reverse and remand.
. Obviously, a totally safe drug does not need comment k protection as it creates no liability.
. The constructive knowledge requirement of danger is different from the usual negligence case. There is constructive knowledge if "by the application of reasonable, developed human skill and foresight” the manufacturer should have known of the danger. 402A comment j.
. The majority opinion implies at least that the element of knowledge had it not been waived would properly be included in plaintiffs verdict-directing instruction. MAI 25.05 utilized in this case does not address knowledge. But MAI 25.06 which is comparable as to the knowledge feature does include defendant’s knowledge. Affirmative defenses are not included in a plaintiffs verdict-director; they are separately instructed on. MAI 3d 32.00.
. I make no judgment as to whether the statute now makes knowledge an affirmative defense in a comment k case, or whether knowledge remains an element of plaintiff’s case.