Captopril is used in the treatment of hypertension, heart failure and other diseases. Captopril is an angiotensin-converting enzyme inhibitor, which mainly reduces sodium retention in the body by inhibiting angiotensin-converting enzyme, blocking the conversion of angiotensin I to angiotensin II, and reducing the production of aldosterone. Captopril can treat all types of hypertension, and it can be used in combination with calcium antagonists such as nifedipine and diuretics such as furosemide to lower blood pressure more effectively. Captopril can also be used in the treatment of improving heart function and is effective in the treatment of chronic heart failure. There are also contraindications to the use of captopril, which is contraindicated in patients suffering from bilateral renal artery stenosis. Some patients may experience adverse reactions such as dry cough, hypotension and proteinuria. The application of captopril should be carried out under the guidance of a doctor to avoid adverse consequences.