Buprenorphine is an opioid agonist-antagonist that has emerged as an option for postoperative analgesia. We compared the postoperative hospital course of patients undergoing open cholecystectomy who received buprenorphine hydrochloride with those who received morphine sulfate. Patients in both groups administered the analgesic using a patient-controlled analgesia infusion device. Comparison of the two groups demonstrated no difference with respect to clinical indicators of intestinal motility, visual analog pain scores and hospitalization period. Postoperative nausea occurred more frequently in the buprenorphine group, but the difference was not significant. We concluded that the patient-controlled analgesia device is a valuable tool for comparing different analgesics. Both analgesics tested provide adequate analgesia with a similar postoperative course.