Evidence for the role of androgens in the male aggressive and sexual behavior is reviewed. Medroxyprogesterone acetate (MPA; Provera, Upjohn) has a marked antiandrogen property; it is effective in lowering the testosterone level and controlling certain otherwise intractable sex deviations. The finding in 6 patients treated for sex deviation are summarized. The effects of MPA in the treatment of 11 temporal lobe epileptics and 5 other patients with severe angry-aggressive behavior disorder are reported. Most temporal lobe epileptics responded well to MPA. Weight gain and earlier sleep were consistent side effects. The values of plasma testosterone, serum luteinizing hormone, and urinary 17-ketosteroids were decreased by the treatment. Four patients were XYY individuals with lack of control over their sexual-aggressive or angry-aggressive impulses.