Medullary diuretics are a type of diuretic. Diuretics can be broadly classified into several types, including medullary diuretics, thiazide diuretics, potassium-protective diuretics, and osmotic diuretics. The medullary collaterals diuretics are commonly used clinically, such as furosemide, torasemide and bumetanide, which mainly act on the thick segment of the ascending branch of the renal medullary collaterals. Because the diuretic effect of medullary collaterals is more powerful, collaterals diuretics can be chosen for patients with significant edema. The side effects of medullary collaterals diuretics mainly lead to hypokalemia, while the effects of thiazide diuretics are relatively mild, and potassium-protective diuretics may lead to the development of hyperkalemia. In addition, osmotic diuretics are commonly used clinically as mannitol.