AbstractOral inhibitors of angiotensin converting enzyme (ACE) now have an established place in the treatment of hypertension and heart failure. Captopril, the first of these agents, was initially used in high doses and was associated with adverse effects including proteinuria, skin rash and taste disturbance. We report 11 patients who developed side effects during captopril therapy (proteinuria two, rash four, taste disturbance four and taste disturbance with rash one) who were subsequently treated with enalapril, a second generation angiotensin converting enzyme inhibitor. Proteinuria did not recur in either patient, skin rash resolved in all five cases and taste disturbance resolved in four of five duringenalaprii therapy. We conclude that the side effects of proteinuria, skin rash and taste disturbance are consequences of captopril idiosyncrasy rather than inhibition of the angiotensin converting enzyme. The reported incidence of these side effects with the current recommended dosage of captopril is low.