SW Legal studies in Business

No Duty to Warn of Possible Allergy to Milk

Appeals court held that consumers could not sue for damages for not being warned that if they were lactose intolerant drinking milk could produce temporary discomfort. Nor do milk producers have an obligation to warn of lactose intolerance, as it is a commonly known problem.

Topic Torts
Key Words

Product Liability; Failure to Warn; Common Knowledge; Milk

C A S E   S U M M A R Y

A group of lactose-intolerant individuals sued nine sellers of milk in a class action suit. They contended that they consumed milk before they were aware of their lactose intolerance and, as a result, suffered temporary gas and stomach discomfort. The plaintiffs claimed the sellers failed to warn of the dangers of lactose intolerance by putting warning labels on milk containers. They sued for damages and for an injunction requiring milk sellers to put this warning label on all milk packaging: “Warning—If you experience diarrhea or stomach cramps after consuming milk, you may be lactose intolerant. Check with your physician.” The district court dismissed the suit. Plaintiffs appealed.


Affirmed. Millions of Americans suffer from lactose intolerance, a genetic condition that prevents them from processing the principal sugar in milk. The plaintiffs contend they were unaware of their intolerance when they purchased milk which caused them to suffer temporary “flatulence, bloating, cramps, and diarrhea” as a result of drinking milk. They contend that milk sellers are aware of this problem, but failed to place warning labels on milk containers. The problem for plaintiffs is that a seller’s duty of reasonable care does not include a duty to warn of risks that should be obvious to or are generally known by users. There is no duty to warn when a danger is commonly known. If producers were required to warn of obvious risks, consumers would pay little attention to warnings about non-obvious, not-generally-known risks. Other widely known risks include alcohol, fast foods, sugar for diabetics, fat that clogs arteries, and common allergies such as for eggs. Since 30-50 million Americans are estimated to be lactose intolerant, this is a commonly known problem for which there is no duty to warn.


Mills v. Giant of Maryland, LLC, 508 F.3d 11 (D.C. Cir., 2007)

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