Thirty-two patients were entered into a double blind trial of antiemetic support in patients being treated with cisplatin. Patients were allocated to receive either oral nabilone (1 mg 8 hourly) or intravenous metoclopramide (1 mg kg-1 3 hourly) in random order over 4 courses. There was no difference between the two treatments in the overall incidence or severity of vomiting, although a subgroup of patients enjoyed a substantial reduction in episodes of vomiting whilst receiving metoclopramide. Side-effects were predictable from the pharmacology of the drugs.