Twenty-eight patients with gynecologic malignancies receiving combination chemotherapy containing cisplatin (80 mg/m2) entered into a randomized controlled trial to evaluate the effect of medical vagotomy for acute cisplatin-induced emesis. Medical vagotomy consisted of 0.5 mg of atropine and 50 mg of hexamethonium bromide, and was injected three times at two hour intervals intramuscularly. A good antiemetic effect (no emesis during the 24 hours after cisplatin administration) was obtained in 40% (6/15) of patients with medical vagotomy but in 0% (0/13) in controlled cases. The time free of vomiting after cisplatin injection (CV time) was statistically prolonged in patients with medical vagotomy (805 +/- 563 min.) when compared with controlled cases (148 +/- 70 min.) (p less than 0.01). Toxicities with medical vagotomy were slight; mild hypotension and dimness of vision only. Individual differences in responding to medical vagotomy were investigated by the acetaminophen method, which showed that high and low responded cases were among these tested patients who had undergone medical vagotomy. In conclusion, medical vagotomy has an excellent antiemetic effect on acute cisplatin-induced emesis without notable side effects. If combined with other antiemetics, a much better antiemetic effect can be expected.