ACEI class antihypertensive drugs are commonly used in clinical antihypertensive drugs. ACEI antihypertensive drugs are angiotensin-converting enzyme inhibitors. The main pharmacological effect of these antihypertensive drugs is to inhibit the activity of angiotensin-converting enzyme and reduce the production of angiotensin II, which leads to vasodilation, blood volume reduction and blood pressure decrease. Inhibition of bradykinin also reduces the degradation of bradykinin. The onset of antihypertensive effect is slow, and the maximum effect is reached in 3-4 weeks. Restriction of sodium intake and combined use of diuretics can lead to rapid onset and enhanced effect. Generally, ACEI drugs end with the word priligy, and these drugs are commonly used in clinical practice, including the following: captopril, enalapril, lenopril, perindopril, ramipril, benazepril, midazepril, fosinopril, etc. ACEI antihypertensive drugs are effective for most mild and moderate hypertension, especially for normal renin type and high renin type hypertension. With the effect of improving insulin resistance and reducing urinary protein, they have better efficacy in hypertensive patients with obesity, diabetes and organ damage such as heart and kidney, especially for patients with chronic heart failure, post-myocardial infarction with cardiac insufficiency, diabetic nephropathy, diabetes and proteinuria. However, it should be noted that ACEI class antihypertensive drugs tend to cause irritating dry cough, with an incidence of 10-20%. These drugs are contraindicated in patients with bilateral renal artery stenosis, hyperkalemia, severe renal failure, and during pregnancy.