How Long Does It Take for Gangrene to Set In?

MedicineNet states that dry gangrene is caused by gradual arterial blockage, as is often seen in diabetics. This kind of gangrene has a slow progression of days to months. Wet gangrene, the result of injury and rapidly cut-off blood supply, nearly always involves infection and can develop over a few hours or days. The resulting sepsis, or blood infection, can become fatal if not treated quickly, warns WebMD.