Diuretics are pharmaceutical agents that promote the excretion of water and electrolytes from the body through urine, helping to reduce fluid retention. They are commonly used to manage conditions such as hypertension, heart failure, and edema. Diuretics are classified into several types, including thiazide, loop, and potassium-sparing diuretics, each with specific indications and mechanisms of action. Their ability to lower blood pressure and alleviate swelling makes diuretics a vital component in cardiovascular and renal management.