Your kidneys remove wastes and extra fluid from your body. Your kidneys also remove acid that is produced by the cells of your body and maintain a healthy balance of water, salts, and minerals—such as sodium, calcium, phosphorus, and potassium—in your blood. Without this balance, nerves, muscles, and other tissues in your body may not work normally.
Your kidneys also make hormones that help control your blood pressure, make red blood cells and keep your bones healthy.