Gangrene is the death and decay of tissue that usually occurs when the blood supply to the tissue is cut off by injury or infection. After the tissue is dead, bacteria may infect the tissue and cause decay.

Gangrene may affect small areas, such as fingers or toes that have been frostbitten, or larger areas of tissue, such as part of the foot. People who have impaired blood flow, such as people with diabetes, may be at higher risk of gangrene if they have skin wounds and infections that are not treated promptly.

Gangrene is treated by restoring blood flow to the affected area, treating any infection, and removing the dead and dying tissue. If it is severe, gangrene sometimes requires that a part of the body, such as a finger, toe, or foot, be amputated.