The application of diuretics in acute renal failure has two main purposes: the first is to diuretic and reduce swelling; the second is to lower blood potassium. Patients with acute renal failure are prone to water and sodium retention, and excessive water load is likely to cause limb edema, heart failure and cerebral edema, the latter two being the more common causes of death in patients. To avoid this, diuretics need to be applied to diuretic swelling, such as furosemide injection and torasemide injection. In addition, patients with acute renal failure are prone to hyperkalemia, which causes malignant arrhythmias, such as ventricular tachycardia, which is also a common cause of death in patients with acute renal failure. The application of diuretics can facilitate the excretion of blood potassium through the kidneys to avoid the above-mentioned conditions.