Does media endorsement for catharsis produce a self-fulfilling or a self-defeating prophecy? In Study 1, participants who read a procatharsis message (claiming that aggressive action is a good way to relax and reduce anger) subsequently expressed a greater desire to hit a punching bag than did participants who read an anticatharsis message. In Study 2, participants read the same messages and then actually did hit a punching bag. This exercise was followed by an opportunity to engage in laboratory aggression. Contrary to the catharsis hypothesis and to the self-fulfilling prophecy prediction, people who read the procatharsis message and then hit the punching bag were subsequently more aggressive than were people who read the anticatharsis message.