There is no consensus for the optimal treatment program for individuals with mild hypertension, including whether treatment should emphasize life-style changes alone, such as weight loss, reduction of sodium and alcohol intake, and increased physical activity, or whether it should also include a pharmacologic component. The dilemma is accentuated by the availability of many drugs from different classes to lower blood pressure. To study the relative efficacy and safety of a combination of pharmacologic and nutritional-hygienic intervention compared with nutritional-hygienic intervention alone, a double-blind, controlled clinical trial was initiated. Nine hundred two men and women with mild hypertension (average blood pressure, 140/91 mm Hg) were randomized to receive nutritional-hygienic intervention plus one of six treatments: (1) placebo; (2) diuretic (chlorthalidone); (3) beta-blocker (acebutolol); (4) alpha 1-antagonist (doxazosin mesylate); (5) calcium antagonist (amlodipine maleate); or (6) angiotensin-converting enzyme inhibitor (enalapril maleate). After 12 months, weight loss averaged 4.5 kg, urinary sodium excretion was reduced by 23%, and reported leisure-time physical activity was nearly doubled. Systolic and diastolic blood pressure in the group given nutritional-hygienic intervention alone (placebo) were reduced by 10.6 and 8.1 mm Hg, respectively. For participants in the five groups receiving antihypertensive medication in addition to nutritional-hygienic treatment, blood pressure reductions were significantly greater than those achieved with nutritional-hygienic treatment alone (range, 16 to 22 mm Hg for systolic and 12 to 14 mm Hg for diastolic blood pressure). Although differences among treatment groups in certain dimensions of quality of life, self-reported side effects, plasma lipid levels, and biochemical measures were observed, no consistent pattern in the differences was noted. Nutritional-hygienic therapy is an effective first-step treatment for persons with mild hypertension, and significant additional blood pressure lowering with minimal short-term side effects can be achieved by adding one of five different classes of antihypertensive agents.