Currently, major categories of antihypertensive agents include diuretics, beta-blockers, calcium channel blockers (CCBs), renin-angiotensin system (RAS) inhibitors [angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARB)]. Among them, RAS (ACE inhibitors and ARB) would be recommended to be a first-line treatment when providing antihypertensive agents for hypertensive patients with diabetes, cardiovascular disease, and impaired renal function. Randomized controlled trials (RCT) of RAS inhibitors compared with other antihypertensive showed a rather lower relative risk (RR). They are all-cause death (RR – 0.95), cardiovascular death (RR – 0.84), incidence of cardiovascular disease (RR – 0.93), and incidence of renal dysfunction (RR – 0.91).