Ten patients with ascites due to chronic liver disease were treated with spironolactone as the sole diuretic in doses of 300 to 600 mg daily. Prior to spironolactone treatment ascites was relatively refractory as indicated by baseline 24-hr urine sodium values of less than 5 mEq and natriuresis of less than 30 mEq following 200 mg hydrochlorothiazide. With spironolactone, mean daily weight loss was 540 g and natriuresis 74 mEq; diuresis was considered satisfactory in nine of ten patients. Untoward effects were limited to a single episode of hepatic encephalopathy, a small fall in serum magnesium in several patients, and three instances of hyperkalemia (5.5, 5.6, and 7.5 mEq/liter). In spite of the tendency to hyperkalemia, urinary potassium excretion increased in seven of the ten patients. There was no rise in serum urea nitrogen or creatinine. Hydrogen ion excretion decreased initially leading to mild hyperchloremic acidosis. Serum urate did not increase.