A large body of evidence from studies in humans, in nonhuman primates, and in smaller laboratory animals has supported a role for serotonin in the modulation of aggressive behavior. The evidence shows that diminished serotonergic function can be linked to aggressive behavior and that treatments that increase serotonergic function reduce aggression. Embedded in this large body of data are studies done specifically with fluoxetine, a serotonin uptake-inhibiting antidepressant drug suggested by some individuals charged with criminal aggression and by their attorneys to cause aggressive violence. Contrary to those charges, extensive studies of fluoxetine in animals have shown that fluoxetine decreases aggressive behavior in various species and models of aggression. Clinical studies of fluoxetine in aggressive behavior have been more limited, but findings in those studies seem consistent with the anti-aggressive effects of fluoxetine found in animal studies.