In summary, ACE inhibitors are effective in reducing blood pressure as initial therapy in some hypertensive patients and in combination with diuretics and other agents in virtually all hypertensives. ACE inhibitors are uniquely advantageous because of their favorable hemodynamic effects, the lack of adverse metabolic effects, and their ability to prevent or blunt undesirable effects of diuretic therapy. Their safety in large numbers of hypertensives has been consistently demonstrated. The minor nature of most side effects and the rarity of life-threatening side effects of ACE inhibitors is reassuring. Clinical experience has provided information about patients likely to be at high risk for side effects with ACE inhibitors enabling avoidance of the drugs, or the use of small doses and careful scrutiny in such individuals. The development of this new class of drugs permits safe and effective blood pressure control with potential enhancement of the sense of well being and quality of life to a degree never before encountered.