The antiemetic action of stimulation of the P6 (Neiguan) acupuncture (ACP) point has been studied in women, premedicated with nalbuphine 10 mg, undergoing minor gynaecological operations under methohexitone-nitrous oxide-oxygen anaesthesia. Invasive ACP--manual or electrical at 10 Hz--applied for 5 min at the time of administration of the premedication markedly reduced the incidence of vomiting and nausea in the first 6 h after operation, compared with untreated controls. This did not occur with stimulation of a "dummy" ACP point outside the recognized ACP meridians. Non-invasive methods (stimulation via a conducting stud or by pressure) were equally as effective as invasive ACP during the early postoperative period. However, both these non-invasive approaches were less effective than invasive ACP in the 1-6 h postoperative period, although each was as effective as two standard antiemetics (cyclizine 50 mg, metoclopramide 10 mg). In view of the total absence of any side effects in more than 500 ACP procedures, the clinical applications of this finding are worthy of further study.