The kidneys regulate the body's fluid volume, mineral composition and acidity. The vital function of kidneys is to separate urea, mineral salts toxins and other waste products from the blood. They preserve water, salt and electrolytes; controls the level of chemicals like sodium, potassium, chloride, calcium, magnesium, sulfate, phosphate and hydrogen. In addition to this, kidneys release three important hormones. They are Erythropoietin (EPO) which stimulates the bones to make red blood cells, Renin which regulates blood pressure and Active form of vitamin D which helps to maintain calcium for bones and for normal chemical balance in the body.

The waste products are generated in the body from normal metabolic processes including the breakdown of active tissues, ingested foods, and other substances. To separate these waste and extra water, the blood enters the kidney through the renal artery, creates urine, which flows to the bladder through tubes called ureters. The clean blood flows back to other parts of the body. This process takes place throughout the life of the kidneys. The kidneys process about 200 liters of blood every day and produce about 2 liters of urine. For maintaining life at least one kidney must function properly.