Generally, your general defense would be that the product did not cause the side effect; something else did.
Also, a defense would be that the plaintiff misused the product.
Where the plaintiff is injured due to an unreasonable misuse of a defective product, contributory negligence will be valid and may bar liability. See McDevitt v. Standard Oil, 391 F.2d 364 (5th Cir. 1968).
Comparative negligence is a valid defense. Most jurisdictions that have adopted comparative negligence will reduce the plaintiff’s recovery in these cases to reflect the fact that plaintiff contributed to his own injuries. See Rudisaile v. Hawk Aviation, Inc., 592 P.2d 175 (N.M. 1979).
Finally, assumption of the risk is also a valid defense. A plaintiff who knows the danger of using a certain defective product and continues to use the product anyway may be held to have assumed the risk. However, in order for assumption of the risk to be a viable defense, the plaintiff must have actually known of the particular danger involved in using the defective product and voluntarily continued to use that product anyway.
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