Enalapril is a new angiotensin converting enzyme inhibitor which, when absorbed by the digestive tract, is converted to enalaprilat. This metabolite is, in fact, the active form of enalapril. Its duration of action is sufficiently long so that enalapril can be administered in a single daily dose. Enalapril has been proved to be a highly effective therapeutic agent which is well tolerated by patients with arterial hypertension or severe congestive heart failure.