INTRODUCTION Aggression is one of the more common problems psychiatrists are called upon to treat, especially in children and adolescents (1). Unfortunately, despite the availability of a variety of treatment approaches, including psychopharmacologic and behavioral (2), there is no well-established and agreed-upon standard treatment for aggression. The purpose of this chapter is to review some of the better data that exist regarding the use of psychopharmacologic agents for reducing aggression. While the neuroleptics and lithium have been used to decrease aggression in adults, the best data have come from studies in children and adolescents. After considering some of the basic concepts concerning diagnosis and assessment, there will be a review of published double-blind and placebo-controlled studies of neuroleptics, lithium, and anticonvulsant agents.