['Ondansetron has a well documented antiemetic prophylactic effect, whereas in most studies of postoperative nausea and vomiting (PONV), metoclopramide is less efficacious. This can be attributed to the short-lasting effect of metoclopramide when a low dose is given at the beginning of surgery. We wanted to test a 20-mg dose of metoclopramide given at the end of surgery, using ondansetron 8 mg as a reference.', '122 patients scheduled for elective laparoscopic cholecystectomy under general anesthesia were studied in a randomized, double-blind study design. At the end of the procedure, the patients received either metoclopramide 20 mg or ondansetron 8 mg intravenously. The patients were observed for 24 h for PONV, pain, side-effects and need for rescue antiemetic medication.', 'No significant differences in the incidence of PONV or need for rescue antiemetic treatment was observed in the 0-24 h postoperative study period. The overall incidence of PONV was 43% in the ondansetron group and 47% in the metoclopramide group. The ondansetron patients had a significantly higher incidence of moderate or strong pain during the postoperative observation period (61% vs. 35% in the metoclopramide group) (P < 0.05). No significant differences in side-effects between the groups were observed.'] Are incidence and severity of postoperative nausea and vomiting similar after metoclopramide 20 mg and ondansetron 8 mg given by the end of laparoscopic cholecystectomies?