Angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) are one of the renin angiotensin system (RAS) inhibitors widely used for the treatment of hypertension. Recently, Blood Pressure Lowering Treatment Trialists' Collaboration (BPLTTC) meta-analysis showed that ACEIs had the blood pressure independent beneficial effects on coronary heart events. In this review, we summarized our current knowledge about ACEIs especially imidapril and re-evaluated ACEIs among other RAS inhibitors (RASIs) because ACEIs have wide ranges of beneficial effects in addition to the ACE inhibition which other RASIs do not have such as the up-regulation of bradykinin level, substance P level, the inhibition of matrix metalloproteinase (MMP) activity and stabilization of coronary plaque.