Twelve patients with severe hypertension of different causes, resistant to conventional antihypertensive agents and also to maximum doses of either minoxidil or captopril added to other combinations, were effectively controlled with the association of small doses of minoxidil and captopril plus a diuretic and a beta-blocker. The untoward effects which were previously present in all the patients with maximum doses of minoxidil and in one of the patients treated with captopril disappeared or greatly diminished shortly after this association was started. The different mechanisms of action and opposite side effects of minoxidil and captopril provide the rationale for a combined treatment with the two drugs.