Purpose: To evaluate the efficacy of dolasetron mesylate in controlling nausea and vomiting in the first 24 hours and to extend these comparisons over the next 4 days in patients receiving moderately emetogenic chemotherapy. Methods: This was a single center, open-labeled study with single arm. Dolasetron (1.8 mg/kg) was given intravenously (I.V.) prechemotherapy with 10 mg of dexamethasone IV, followed 24 hours later by oral dolasetron (200 mg once daily) for the subsequent 4 days. The frequency of vomiting, severity of nausea and the presence of rescue antiemetics were assessed daily. Results: Of 30 patients enrolled, 28 were eligible and evaluable for the efficacy. Four out of 28 patients had complete control of nausea and vomiting without any rescue antiemetics through 5 days. The complete control got better as time went by with the rates of 17.9/46.4/42.9/53.6/60.7% on days 1 to 5. Vomiting was better controlled than nausea in both cisplatin-containing and non-containing chemotherapy. The adverse events were mild to moderate degrees of headache, diarrhea and fever, but were recovered spontaneously. Conclusion: Dolasetron was effective and safe for the control of nausea and vomiting in the patients with moderately emetogenic chemotherapeutic agents.