In a randomised, double-blind and parallel-design multicentre study, 282 chemotherapy-naive cancer patients received tropisetron 5 mg intravenously (i.v.) before high-dose cisplatin on day 1, and oral tropisetron 5 mg daily on days 2-6, in combination with either placebo (n = 143) or dexamethasone (n = 135), given i.v. on day 1 and orally on days 2-6. Complete protection from acute vomiting/nausea was achieved in 76.3%/79.3% of patients receiving the combination and in 55.2%/61.5% of those receiving tropisetron alone. Complete protection on days 2-6 from delayed vomiting/nausea was obtained in 60%/60% and 39.2%/40.6%, respectively. Tropisetron in combination with dexamethasone is safe and more effective than tropisetron alone in the prevention of both acute and delayed cisplatin-induced emesis.