The anti-emetic effect, safety and clinical usefulness of ondansetron for the treatment of nausea and vomiting caused by anticancer drugs including cisplatin, was evaluated by a multi-institutional study in patients with various malignancies. In this study, ondansetron was given intravenously with mainly a single dose of 4 mg to intervene nausea and vomiting. 1. Efficacy ratio of overall effects on nausea and emesis observed for 24 hours after treatment was 69.8%. 2. No side effect was observed. Laboratory tests showed temporary elevation of serum uric acid level in 1 patient in the group given 4 mg. 3. From these results, it seems that ondansetron, given intravenously after initial vomiting, was highly safe and clinically useful anti-emetic for the treatment of nausea and vomiting associated with anti-cancer drugs.