Sixty patients undergoing day-case dental surgery were either given sublingual buprenorphine 0.2 mg or 0.4 mg or a buffered placebo 1 hour prior to general anaesthesia. Pre-operative anxiety was not allayed and there was no significant analgesia afforded by buprenorphine in the immediate postoperative period. The synthetic opiate depressed psychomotor function and both 0.2 mg and 0.4 mg buprenorphine yielded a significantly higher incidence of postoperative nausea and vomiting.