Diuretic therapy—the conventional treatment for hepatic oedema—is not always effective. A phase III trial has now shown that tolvaptan (7.5 mg daily) is effective as an add-on therapy for 7 days in the treatment of hepatic oedema associated with liver cirrhosis. Tolvaptan decreased body weight and improved lower-limb oedema and ascites-related symptoms in patients (n = 84) considerably more than placebo (n = 80). Tolvaptan also increased serum sodium concentration irrespective of the baseline level.