Ketamine, as the sole anaesthetic agent, was assessed in a double-blind study of 135 female patients who underwent Iaparoscopic sterilization. The patients were allocated randomly to one of four groups according to the type (pentobarbitone or droperidol) and route (i.v. or i.m.) of premedica-tion. In addition all the patients received hyoscine i.m. Neither pentobarbitone nor droperidol prevented adverse emergence reactions and the total frequency of dream-like activity. However, patients who received pentobarbitone i.v. did not recall unpleasant dream-like activity. Patients who received droperidol i.v. had the shortest recovery time after ketamine anaesthesia. There was a high incidence of visual disturbances in all groups. Droperidol protected against the initial increase of heart rate, and pentobarbitone against the increase in arterial systolic pressure associated with ketamine.