Gangrene is a condition that occurs when body tissue dies. It is caused by a loss of blood supply due to an underlying illness ( Diabetes , Atherosclerosis , Peripheral arterial disease , Smoking , Trauma or serious injury , Obesity , Raynaud's phenomenon or Weakened immune system) , injury, and/or infection. Fingers, toes, and limbs are most often affected, but gangrene can also occur inside the body, damaging organs and muscles. There are different types of gangrene and all require immediate medical attention.