Despite modern anaesthetic procedures, postoperative nausea and vomiting are still the side-effects most often mentioned: acupressure is reported to be an additional method of preventing these effects in minor gynaecological surgery. We investigated the effectiveness of acupressure in patients undergoing gynaecological operations of longer duration (6-8 h) in a verum acupressure group compared to a placebo group. Before beginning the study we investigated a control group to find out the frequency of emesis. In the worst case of nausea that we encountered, 80% in the 0-6 h postoperative period, the number of random samples for the acupressure and placebo groups was calculated (30 patients in each group). The error for alpha was established at 5% and the reduction of nausea was 50%. METHODS. The female patients were 18 to 65 years old (ASA group I and II). Acupressure was carried out by fastening small metal bullets at the point P 6 to each forearm by means of an elastic bandage. The bullets were left there for 24 h. The premedication anaesthesia, postoperative analgesia, and antiemetic treatment were standardized. During a 24-h period we investigated the incidence of nausea and vomiting. RESULTS. The anthropometric data, the duration of surgery and the amount of postoperative analgesia were comparable between the three groups. Verum acupressure obtained a statistically significant and relevant reduction in nausea up to the 6th postoperative hour in comparison with the placebo group (P = 0.03). Nausea was reduced from 53% in the placebo group to 23% in the acupressure group. CONCLUSION. As demonstrated in this group of longer gynaecological surgery patients as well as in chemotherapy-induced nausea and vomiting, we were able to demonstrate that acupressure is an effective method of preventing nausea and vomiting without any side-effects. It is a valuable addition to the prevention of postoperative nausea and vomiting. Further studies should be conducted to investigate this possibility further.