Many mass tort and toxic tort actions assert claims for product liability based on failure to warn. The plaintiff claims that the manufacturer of the product had a duty to warn of a dangerous characteristic of the product. However, a manufacturer need not warn of every hazard. “Modern life would be intolerable unless one were permitted to rely to a certain extent on others doing what they normally do, particularly if it is their duty to do so.”

A manufacturer’s duty to warn may be discharged when the person using or controlling the use of the product is or should be aware of the dangers associated with it. This is the sophisticated user and/or sophisticated intermediary defense. This article discusses the legal background for this defense from the Restatement (Second) of Torts, points out the differences between the sophisticated intermediary and sophisticated user defenses, and reviews how courts have recently analyzed these defenses. As the cases cited in this article demonstrate, this doctrine is typically raised in a dispositive motion, but it may also be submitted to the jury as an instruction…