## Facts

- Plaintiffs alleged injuries from in utero exposure to diethylstilbestrol (DES) prescribed to their mothers to prevent miscarriage.
- Plaintiffs sued over 170 prescription-drug manufacturers, including Abbott Laboratories, asserting design-defect strict liability, failure to warn, breach of warranty, and fraud.
- Because plaintiffs could not identify the specific manufacturer of the DES ingested, they invoked market-share liability under prior California precedent for DES cases.
- The trial court ruled, in substance, that prescription-drug makers could not be held strictly liable for design defects, but could face liability for inadequate warnings of known or reasonably knowable risks.
- The trial court also ruled that breach of warranty and fraud could not proceed under market-share liability, and that defendants were not jointly and severally liable; each could be liable only in proportion to its DES market share.
- Plaintiffs sought writ relief; the Court of Appeal denied relief and upheld the trial court’s approach.
- The California Supreme Court granted review in an extraordinary-writ posture to resolve the challenged pretrial rulings and their relationship to California products-liability and DES market-share doctrine.

## Issues

1. Whether prescription-drug manufacturers may be held strictly liable for design defects in their drugs.
2. Whether strict liability for failure to warn in the prescription-drug context extends beyond risks known or reasonably scientifically knowable at the time of distribution.
3. Whether market-share liability permits claims based on fraud or breach of warranty when the specific manufacturer cannot be identified.
4. Whether defendants sued under market-share liability are jointly and severally liable for all damages or only severally liable in proportion to market share.

## Decision

- The court held that prescription-drug manufacturers are not subject to strict products liability for design defects.
- The court confirmed that manufacturers may be held liable for inadequate warnings, limited to risks known or reasonably scientifically knowable at the time of distribution.
- The court held that market-share liability does not support fraud or breach-of-warranty theories when causation as to a particular defendant is not shown.
- The court held that market-share defendants are not jointly and severally liable; each defendant’s liability is limited to its proportionate share of the relevant DES market.
- In practical effect, the court affirmed the core limitations imposed by the trial court and approved market-share-based apportionment.

## Legal Principles

- Prescription drugs fall within the “unavoidably unsafe products” policy reflected in Restatement (Second) of Torts § 402A cmt. k: when properly prepared and accompanied by adequate warnings, they are not treated as defectively designed for strict-liability purposes.
- Strict products liability for prescription-drug injuries remains available for manufacturing defects and for failure to warn, but not for design defect.
- Warning liability in the prescription-drug setting is constrained by a knowledge standard: no liability for failing to warn of risks that were not known or reasonably scientifically knowable at the time of distribution.
- Market-share liability is a limited causation substitute tailored to the DES context and does not extend to fraud or breach-of-warranty theories that would impose liability without product identification.
- Under market-share liability, damages are allocated severally according to each defendant’s share of the relevant market, rather than imposed jointly and severally.

## Conclusion

The court barred strict design-defect liability for prescription drugs, limited warning-based liability to known or reasonably knowable risks at distribution, and confined DES market-share litigation by disallowing fraud and warranty theories and requiring several, market-share-based apportionment of damages.


Brown v. Superior Court, 44 Cal. 3d 1049, 751 P.2d 470 (Cal. 1988)