Forty-six patients with ovarian carcinoma who received single drug cisplatin chemotherapy were evaluated for the antiemetic efficacy of two different doses of metoclopramide. Each patient received during the first two courses a 4-hour continuous infusion of either 8 or 0.8 mg/kg in a random order. Total protection from emesis was achieved in 12 (26%) of the high-dose courses and in three (7%) of the low-dose courses of metoclopramide. Major control (one or two emetic episodes) was achieved in seven (16%) and in four (9%) of the courses, respectively. The higher dose of metoclopramide significantly reduced the degree of nausea as recorded on a visual analogue scale. A significant difference between courses 1 and 2 could only be seen when the high-dose treatment was followed by low-dose metoclopramide. The duration of anorexia after the courses was not influenced by the metoclopramide dosage. Side effects were mild. It is concluded that there is a dose-response relationship for the antiemetic effect of metoclopramide.