concurring.
Although I join the majority opinion, I write separately in order to articulate my understanding of what the majority holds and to distinguish certain cases relied upon by the defendant.
This appeal involves Counts IV and V of the plaintiff’s amended complaint. Count IV alleged that since adequate testing prior to distributing DES would have revealed that DES was both highly carcinogenic and ineffective in preventing miscarriages, the defendant was negligent in marketing DES at all. Count V alleged that the defendant breached implied warranties because the DES ingested by the plaintiff’s mother was unfit for its intended use (i.e., was defective) and caused the plaintiff to develop vaginal adenosis. The district court ruled that the plaintiff could not present either of these theories. According to the district court, Michigan law does not recognize implied warranty theories in products liability cases involving drugs. Moreover, the court held that although the plaintiff could proceed under a negligence theory, the only such theory cognizable under Michigan law in this drug case was that the defendant had provided inadequate warnings to physicians about the potential risks associated with use of DES. The district court refused to permit the plaintiff to proceed on the broader theory that the defendant was negligent in marketing DES at all.1
I agree with the majority that under Prentis v. Yale Manufacturing Co., 421 Mich. 670, 365 N.W.2d 176 (1984), this case must be returned to the district court. In *98this case, as in Prentis, it is alleged not that one unit of a product line was defective but that the entire product line was defectively designed. Prentis teaches that in such cases the plaintiff must prove negligence even if it proceeds under an implied warranty theory. Accordingly, on remand Bogorad will be limited to the negligence theory articulated in Count IV.2
Turning to the specifics of Bogorad’s negligence theory, the defendant contends that under Smith v. E.R. Squibb & Sons, Inc., 405 Mich. 79, 273 N.W.2d 476 (1979), the only theory under which the plaintiff may proceed is that the defendant inadequately warned physicians of the dangers associated with DES. The defendant misreads Smith. Although Smith does hold that a drug manufacturer must warn the medical profession of “any risks inherent in the use of [a] drug which the manufacturer knows or should know to exist,” 405 Mich, at 88, 273 N.W.2d 476, Smith does not hold that the inadequate warning theory is the only theory available to prospective plaintiffs. Indeed, the Smith court had no occasion to discuss other negligence theories because the plaintiff in that case pleaded only that warnings had been inadequate.
The general rule in Michigan is that a manufacturer must perform such tests as are reasonably necessary in order to insure that a product is safe. See Ebers v. General Chemical Co., 310 Mich. 261, 274-75, 17 N.W.2d 176 (1945); Selmo v. Baratono, 28 Mich.App. 217, 226, 184 N.W.2d 367 (1970). The plaintiff in this case has alleged that had the defendant tested DES adequately, it would have discovered that the drug was highly carcinogenic and was ineffective in preventing miscarriages. If a jury were to accept these allegations, then the jury reasonably could conclude that the defendant was negligent in ever marketing DES because the marginal utility of the drug did not outweigh the serious health risks involved. See Moning v. Alfono, 400 Mich. 425, 254 N.W.2d 759 (1977).
The defendant also relies upon Hasler v. United States, 517 F.Supp. 1262 (E.D.Mich.1981), rev’d on other grounds, 718 F.2d 202 (6th Cir.1983), cert. denied, — U.S. -, 105 S.Ct. 84, 83 L.Ed.2d 31 (1984) and Keil v. Eli Lilly & Company, 88 F.R.D. 296 (E.D.Mich.1980) (unpublished). Hasler is distinguishable. The plaintiff is that case alleged that the defendant had been negligent in testing swine flu vaccine and in warning about the potential health risks. The district court found the defendant liable on the inadequate warning theory without discussing the inadequate testing claim. The court did not hold that only the inadequtae warning theory was cognizable under Michigan law.
It must be acknowledged that the district court did so hold in Keil. Since the district court’s opinion in Keil is devoid of analysis on this point, however, the decision has little persuasive value. Plaintiff Bogorad has stated a claim upon which relief can be granted in Count IV of her complaint. The district court should have permitted her to proceed under that theory.
With these comments, I join the opinion of the majority.
. Implicit in the plaintiffs position is that the defendant was negligent in ever marketing DES regardless of the nature or extent of any warnings provided.
. Although Prentis does “not suggest that implied warranty and negligence are not separate and distinct theories of recovery," see 421 Mich, at 692, 365 N.W.2d 176, it does hold that in cases alleging a defective design the jury is to be instructed only on negligent design. Separate instructions on implied warranty — which would be identical to the negligence instructions— would be “repetitive and unnecessary.” Id. at 691, 365 N.W.2d 176.