The sedative properties of trazodone were the object of a double blind study in dental out-patients, comparison being made with diazepam. It was observed that oral trazodone possesses considerable tranquillizing activity. It has no side-effects either after intake or during return home. The use of capsules containing 50 mg of trazodone is recommended. At this dose, sympathetic hyperactivity is also inhibited. Diazepam doses of 15 mg lead to mental sedation and inhibition of symptoms due to sympathetic hyperactivity but, unlike trazodone, diazepam possesses hypnotic acitivity and side-effects that make its use dangerous in patients who cannot be taken home by somebody else, or who have to drive a car.