In 36 patients with normal renal function receiving hydrochlorothiazide and propranolol, lying diastolic blood pressure remained above 95 mmHg. In a double-blind trial, Step 3 therapy with 5-40 mg/day of minoxidil reduced blood pressure somewhat more effectively than 25-200 mg/day of hydralazine. The percentage of patients with lying diastolic blood pressure below 90 mmHg was 69 versus 35% at four weeks, and 55 versus 40% at 28 weeks. Transient falls in blood pressure within 4 h of any dose were greater with hydralazine which usually needed to be given in divided daily doses. Minoxidil caused tachycardia, and more adverse effects. Minoxidil is more effective, produces more consistent blood pressure control throughout the day, and may often be administered once daily.