A five-drug parenteral antiemetic regimen was administered to 17 patients experiencing intractable vomiting following treatment with cisplatin-containing combination chemotherapy. The five-drug treatment consisted of metoclopramide (1 mg/kg iv), diphenhydramine (50 mg im), dexamethasone (20 mg iv), diazepam (5 mg iv), and thiethylperazine (10 mg im), given together at the initiation of the regimen and repeated on a predefined schedule. The number of emetic episodes, duration of nausea and vomiting, and adverse effects were recorded by trained observers. In addition, all patients completed standardized evaluation forms on the day after treatment. Thirteen patients (76%) remained free of vomiting and three (18%) had only one emesis after beginning the study treatment. No serious toxicity was encountered. We conclude that intractable vomiting induced by cisplatin-based combination chemotherapy can be successfully terminated with an aggressive parenteral antiemetic regimen.