<p>Perindopril is an ACE inhibitor. It works by blocking the action of angiotensin converting enzyme (ACE). ACE produces angiotensin II, as part of the body&#39;s natural control of blood pressure. Angiotensin II causes blood vessels to constrict and narrow, which increases the pressure within the blood vessels. Perindopril blocks the action of ACE, it reduces the production of angiotensin II, thus allows the blood vessels to relax and widen. The overall effect of this is a drop in blood pressure.</p>