The psychopharmacology of aggression in humans typically focuses on physical, active, and direct aggressive acts. This chapter focuses aggression directed outside of one's self. J. M. Halperin's study implies that there is perhaps a developmental lesion that begins as aggression in children and may change as maturation resulting in variation in adult aggressive behavior. The medications most widely employed in the treatment of aggression, regardless of etiology, include major tranquilizers, antidepressants, and mood stabilizers. PRN medicines, or pro re nata, according to circumstances, constitute a common method for treating the acute aggression. The risk/benefit ratio of these medications must be considered as well as monitoring for side effects. Psychologic treatment modalities, including individual therapy, family treatment, and group therapy, either in the context of an outpatient or inpatient setting, should compliment pharmacotherapy. Behavioral therapy can be especially useful for the aggressive patient.