The Treatment of Mild Hypertension Study (TOMHS) is a randomized, double-blind clinical trial currently being conducted to compare the effects of nonpharmacologic therapy alone with those of 1 of 5 active drug regimens combined with nonpharmacologic therapy, for long-term management of patients with mild hypertension. Six classes of drugs were studied: (1) acebutolol (beta blocker), (2) amlodipine (calcium antagonist), (3) chlorthalidone (diuretic), (4) doxazosin (alpha 1 antagonist), (5) enalapril (angiotensin-converting enzyme inhibitor) and (6) placebo. All participants received nutritional-hygienic advice to reduce weight and sodium and alcohol intakes and to increase physical activity. End points include blood pressure change, side effects and quality-of-life indices; incidence of electrocardiographic and echocardiographic abnormalities; and incidence of cardiovascular clinical events, including death, among participants receiving drugs as first-step treatment as well as nonpharmacologic treatment compared with incidence among those participants randomized to nonpharmacologic treatment only as the initial step.