The influence of a once daily dose of 200 mg celiprolol alone and in combination with 12.5 mg chlorthalidone on uric acid and electrolyte metabolism was investigated in 22 hypertensive patients with gout in a randomized trial. All patients were treated with allopurinol and diet. A four weeks treatment with celiprolol (11 patients) showed no influence on uric acid metabolism, electrolytes, blood glucose, cholesterol and triglycerides. Under treatment with celiprolol plus chlorthalidone (11 patients) only a small rise in serum uric acid was observed after four weeks but at the same time uric acid clearance and excretion increased significantly. There was no obvious change in serum electrolytes but an increase in sodium, potassium and chloride urine excretion. Serum uric acid, uric acid clearance and excretion decreased during a 6 months treatment period. A small decrease in cholesterol and triglycerides was observed. Blood pressure decreased in both treatment groups but there was only a small change in heart rate.