The dose-response relationship of ramipril was examined in 216 subjects with mild-to-moderate essential hypertension in a double-blind, placebo-controlled, multicenter study. Ramipril capsules (1.25, 2.5, 5, or 10 mg) or placebo capsules were administered once daily for 12 weeks. Significant reductions in supine and standing diastolic and systolic blood pressures were seen at end point in the ramipril 2.5, 5, and 10 mg treatment groups compared with placebo. The antihypertensive effect was greater at higher doses. The minimum effective dose of ramipril was 2.5 mg once daily.