Droperidol 5 mg and 10 mg and diazepam 10 mg were compared in premedication studies with morphine 10 mg and saline. Droperidol caused less hypnosis than either morphine or diazepam, and its use was associated with a much higher incidence of anxiety among patients than was observed in the group who had received saline only. Dizziness and restlessness were also significant features of the action of droperidol. There was no evidence of any gross effect on cardiovascular system stability. The incidence of sickness following droperidol was similar to that in the saline and diazepam groups.