Five patients presenting with severe hypertension who failed to exhibit diastolic blood pressures less than 120 mm Hg following the oral administration of propranolol (60--80 mg) and furosemide (40 mg) received minoxidil (20 mg, p.o.). Systemic blood pressure, heart rate, and cardiac output were measured prior to and hourly following the addition of minoxidil to the regimen of propranolol and furosemide. One hour following the addition of minoxidil, systemic blood pressure decreased from 204/126 to 186/114 mm Hg (mean systolic/mean diastolic blood pressure). Four hours after minoxidil administration, systemic blood pressure was 175/105 mm Hg. Four of the 5 subjects exhibited diastolic blood pressures greater than 100 mm Hg at 4 hr and were given a booster dose of minoxidil (5--20 mg). Systemic blood pressure subsequently decreased to 153/92 mm Hg at 8 hr and to 142/86 mm Hg at 12 hr following the initial dose of minoxidil. The reduction of systemic blood pressure was achieved without significant change in heart rate or cardiac output. These data indicate that stepped-care therapy utilizing a diuretic, a beta-blocking agent, and minoxidil produces prompt, significant, and sustained reduction of systemic blood pressure in patients with severe, potentially life-threatening hypertension.