Twenty-five hyperkinetic, emotionally disturbed children were treated with chlorpromazine for periods lasting from 4 to 16 months. They also served as their own controls by receiving placebo medication for 4 to 6 weeks during some phase of treatment. Response was determined from the following observations: (1) Clinical changes noted by the clinic staff which included the social worker and psychologist as well as the therapist; (2) data from the home environment; (3) reports from the school counselors; (4) changes in the battery of psychological tests done before and after treatment.Improvement in varying degrees was noted in 21 cases—84%, and was marked in 70%. Diminution in hyperactivity was the outstanding phenomenon. Combativeness was reduced considerably. There was definite improvement in willingness to learn.The psychological testing suggested that the learning process was facilitated. Trends toward increased emotional control were evidenced although the basic personality seemed unchanged.The procedure was effective because an "improved interpersonal relationship" could be established and exploited for the sake of the learning process.The side effects were minimal compared with those of adults and did not necessitate the termination of treatment in any case. Sequential blood count studies were negative.It is suggested that, perhaps for the first time, we have a drug which dampens the primitive fight-flight responses, possibly actuated by the "arousal system" of Magoun (15). It is further suggested that by controlling this basic mechanism without impairing consciousness and the learning process, we can now do more effective psychotherapy.We seem to have entered the era of "combined therapy" where drug therapy and psychotherapy are complementary and can be combined to change the personality most effectively.