Metolazone [2-methyl-3-(0-tolyl)-6-sulpharnyl-7-chloro-1, 2, 3, 4-tetra hydro-4-quinazolinone] is recently introduced as a new orally acting diuretic. It is structurally related to sulfonamides and benzo-thiazidines. 41 male patients suffering from generalised edema due to various causes including 7 cases of congestive cardiac failure, 6 cases of malnutrition and 28 cases of hepatic cirrhosis were treated with metolazone given orally in a dose varying from 5 to 60 mg per day. The optimum effective dose was found to be 5 mg per day. 36 cases responded well with a loss of body weight ranging from 2.5 kg. to 12 kg. There was a significant increase in the urine volume and the urinary sodium, potassium and chloride excretion. Saluretic response was marked. Urinary sodium increased from 8-20 mEq/ day to 100 to 120 mEq in 24 hours. No serious side effects were observed during this study. Hypokalemia and hyponatremia occurred on increase of the dose. Occasionally leg cramps and abdominal distress were observed. Metolazone was found to be an effective orally active diuretic in a dose of 5 to 10 ^, mg/day.