The clinical response to a monamine oxidase inhibitor and a sympathomimetic amine or tyramine containing foodstuffs have been studied in four patients with idiopathic postural hypotension. Each was receiving fludrocortisone acetate therapy. One patient has had substantial clinical improvement for over 26 months on the combination and another improved symptomatically for nine months before further neurologic deterioration. One patient with additional chronic polymyositis had little change in symptoms. Another with milder manifestations of the syndrome had intolerable headaches with the therapy. Maintenance of blood volume was a necessary though not sufficient condition for symptomatic improvement with the regimen.