Abstract The preoperative sedative and hypnotic effects of a new complex of chloral hydrate and betaine (chloral betaine) has been evaluated in 100 patients undergoing elective dental procedures. Chloral betaine was given 60 to 90 minutes prior to the procedure. Children under 11 years of age were given one 435 mg. tablet, and patients over 11 years were given two 435 mg. tablets. Preoperative sedation was obtained in ninety-five of 100 patients. All patients were more easily aroused and more alert after chloral betaine than when barbiturates were used preoperatively. Patients with cerebral palsy were found to be more cooperative, to have better neuromuscular relaxation, and to permit more extensive treatment than when sedated with barbiturates. It appears that chloral betaine offers the advantages of chloral hydrate without its limitations. It does not have the rebound effect of chloral hydrate, in that there is no aftertaste or gastrointestinal irritation.