The antihypertensive effects of the selective alpha 1-adrenoceptor antagonist, terazosin, in black patients with uncomplicated, mild to moderate essential hypertension were examined retrospectively in seven randomized, double-blind, placebo-controlled trials conducted in the United States. Following 4 to 13 weeks of treatment with terazosin (2-40 mg, once daily), supine and standing systolic and diastolic blood pressures were decreased significantly from baseline, and these decreases were significantly greater than those observed in the placebo group (P less than 0.05). Blood pressure changes in the black and white patient subgroups were comparable. Terazosin was generally well tolerated with a low incidence of serious side effects. We conclude that terazosin is a safe and effective antihypertensive agent in black patients with essential hypertension.