OBJECTIVE To evaluate the clinical efficacy of ramosetron hydrochloride in the combination with dexamethasone for the prevention of nausea and vomiting induced by cisplatin. MATERIAL AND METHOD Thirty in-patients with malignant tumor being treated with cisplatin at a dose of 70 mg/m2 or more for a total of 94 cycles were scheduled to receive ramosetron 0. 3 mg IV given 30 minutes before chemotherapy and dexamthasone 20 mg IV on day 1 for the prevention of acute emesis and continued with ramosetron tablet 0.1 mg one tablet orally one hour before chemotherapy or in the morning in case of no chemotherapy scheduled and dexamethasone capsule 5 mg 2 capsules twice daily on day 2 to day 5 for the prevention of delayed emesis. The evaluation period started concomitantly with the start of chemotherapy (hour 0) and continued until 24 hours after completion of chemotherapy. The antiemetic efficacy of ramosetron plus dexamethasone was analyzed according to the occurrence of nausea and vomiting within 24 hours of treatment cycle. The study emphasized both on acute and delayed emesis control. ASSESSMENT The degree of severity of nausea was determined according to the following criteria: 0: None: nausea does not occur, 1: Mild: slight nausea but no disruption to daily acitivites, 2: Moderate: nausea and some disruption to daily activities, 3: Severe: extreme nausea and severe disruption to daily activities. The control of vomiting episodes was determined according to the frequency of vomiting (including retching) as the following criteria: Complete: 0 emesis episode, Major: 1-2 emesis episodes, Minor: 3-5 emesis episodes, Failure: > 5 emesis episodes. RESULTS The result of all 94 cycles of the first day of treatment on acute emesis (0-24 hours) were none 80.9%, mild 18.1%, and moderate 1.1% for nausea episode. For the vomiting control were complete 81.9%, major 16%, minor 1.1% and failure 1.1% respectively. The efficacy of the prevention of delayed emesis (day 2 to day 5) for nausea episode were 67%, 66%, 70.2%, and 75.5% no nausea respectively. For the vomiting control were 75.5%, 74.5%, 86.2%, and 88.3% complete control on day 2 to day 5. No serious adverse events occurred. Hiccups, constipation, and dull headache were reported as the common side effects of ramosetron. CONCLUSION Ramosetron combined with dexamethasone is effective for the prevention of both acute and delayed emesis associated with cisplatin. The prevention of acute emesis seems to be more effective than the prevention of delayed emesis. Adverse events were mild. No serious side effects occurred in the present study.