Forty-one patients treated with cisplatin (100-120 mg/m2), alone or associated with vindesine (3 mg/m2), were included in a randomized crossover pilot study which compared 3 different doses of intravenous clebopride with intravenous metoclopramide. The patients were randomly assigned to receive clebopride in the first chemotherapy course in one of the three dose levels used (0.5 mg/kg, 21 patients; 0.75 mg/kg, 11 patients; 1 mg/kg, 10 patients) or metoclopramide (10 mg/kg). In the second course of the same chemotherapy the patients received the alternative antiemetic, and thus each patient was his own control. The total dose of both antiemetic drugs was infused in 5 intravenous fractions given every 2 hours. The antiemetic activity of clebopride was moderately lower to that of metoclopramide with the first two tested doses (overall doses of 0.5 and 0.75 mg/kg) and similar with the last dose (1 mg/kg). Clebopride was reasonably well tolerated at the used dosages, inducing sedation in 20% of cases (versus 24% with metoclopramide) and diarrhea in 37% (versus 20% with metoclopramide). Extrapyramidal reactions developed in 17% of the courses which included metoclopramide and in none including clebopride. This difference was statistically significant.