Objective: To investigate the efficacy and safety of 14 days' orally administered tolvaptan as adjunctive treatment for hepatic oedema in Japanese liver cirrhosis patients with insufficient response to conventional diuretics, with the option to increase dose in those who did not respond initially. Methods: This multicentre, single-arm, phase 3 study allocated patients with liver cirrhosis and persistent ascites to 7-day treatment with 7.5 mg/day tolvaptan followed by an additional 7 days' treatment. Responders at day 7 (achieving !1 kg body-weight reduction) continued on 7.5 mg/day tolvaptan; nonresponders (<1 kg body-weight reduction) received 15 mg/day tolvaptan. Conventional diuretic treatment continued throughout. The primary endpoint was change in body weight from baseline, as a marker of ascites volume. Results: A total of 51 patients received 7.5 mg/day tolvaptan for 7 days, which caused a significant reduction in mean body weight (55% response rate). During the second 7-day treatment period, 30 patients received 7.5 mg/day tolvaptan and 13 patients received tolvaptan 15 mg/day: response rates were 43% and 23%, respectively. Two serious adverse events were observed. Serum sodium was within normal range.