OBJECTIVE To compare the antiemetic effects of metoclopramide and hyoscine in patients after laparoscopic cholecystectomy. METHODS Prospective, randomised trial. METHODS University hospital, Sweden. METHODS 100 consecutive patients median age 49 years (range 21-79) of whom 9 were withdrawn after randomisation. METHODS Patients were randomised to receive either four doses of metoclopramide 10 mg intravenously starting at the induction of anaesthesia (n = 44), or hyoscine transdermally through a patch placed behind the ear at 0600 h on the day of operation (n = 47). METHODS The incidence of nausea and vomiting. RESULTS Metoclopramide was significantly more effective at preventing both nausea and vomiting (20/44 (45%) compared with 32/47 (68%), p < 0.05, and 10/44 (23%) compared with 21/47 (45%), p < 0.05). Women were significantly more likely to become nauseated than men (46/66 (70%) compared with 5/25 (20%), p < 0.001). Two patients in the metoclopramide group developed dizziness, and one patient in the hyoscine group had a disturbance of vision. About 20% in each group required additional antiemetic treatment. The median hospital stay in both groups for patients who did not develop complications was 2 days. CONCLUSIONS There was a high incidence of nausea and vomiting after laparoscopic cholecystectomy even after treatment with metoclopramide. Further measures are indicated, particularly for women.