The efficacy, safety and usefulness of oral granisetron for nausea and vomiting induced by the administration of anticancer drugs were compared among four doses using the subjects registered through telephone calls by the physicians-in-charge. The clinical efficacy of the drug was assessed as "remarkably effective" or "effective" in 50.0% (11/22) in the 0.5 mg group. 68.4% (13/19) in the 1 mg group, 81.0% (17/21) in the 2 mg group and 78.3% (18/23) in the 4 mg group. The antiemetic effect of the drug persisted for approximately 24 hours in the 2 mg and 4 mg groups. No adverse event or abnormal laboratory value fluctuation which might pose a clinical problem was observed. From these results, single administration of oral granisetron at a dose of 2 mg once a day was considered to be the optimal administration and dosage for nausea and vomiting induced by the administration of anticancer drugs.