Angiotensin is an oligopeptide hormone. Angiotensin, also known as vasoconstrictor and angiotensin, is an oligopeptide hormone that is an important component of the renin-angiotensin system. Angiotensin causes vasoconstriction and elevated blood pressure; it promotes the release of aldosterone from the adrenal cortex. It also has a strong thirst-quenching effect. Under normal circumstances, due to the low secretion of renin in the blood and the low level of angiotensin, it has no significant effect on blood pressure regulation. Patients should be aware of acute kidney injury, hypotension and hyperkalemia when using renin angiotensin inhibitors. Dehydration and hypotension may occur in the elderly after use, predisposing them to acute kidney injury. Plasma hormone and plasma aldosterone levels are prone to decrease after drug administration, leading to hyperkalemia. If any physical discomfort occurs, go to the hospital immediately.