Should a plaintiff be allowed to recover if his illegal conduct contributed to his injury?

Even after the adoption of comparative negligence in most jurisdictions, there are still some that recognize some complete defenses based on an evaluation of the plaintiff's conduct. One such defense is based on the doctrine of "in pari delicto," which essentially states that a plaintiff should not be allowed to recover if the plaintiff’s illegal activity was the reason the plaintiff got hurt - if the injury is the result of the risk the statute was enacted to prevent in the first place. Here is a recent case that discusses this doctrine. The facts of the case are essentially these: A woman got a prescription for a diet pill, bought the pills but did not use them all. Her husband, who did not have a prescription for it, took the left over pills. Years later, he was diagnosed with a fatal condition that arguably can be traced to the use of the pills. The widow filed a wrongful death action and the question is whether she should be allowed to recover since it can be argued that either her conduct in allowing the decedent to take medication was illegal, or that the conduct of the decedent in taking the medicine without a prescription was illegal. The court decided that the issue was for the jury stating that "we cannot say that, as a matter of law, plaintiffs are barred from relief. This is a question for the jury to decide. The Latin phrase “in pari delicto” literally means “in equal fault.” We simply cannot conclude at this stage of the case that [the decedent], who took his wife's prescription drugs, was in pari delicto or inequal fault with [defendant]." In other words, the court applied a comparative negligence approach by suggesting the application of the in pari delicto doctrine depends on a comparision of the relative culpability of the parties. For a comment on this case, go to the Drug & Device Law Blog.