A device – usually a rubber cord or tight bandage – that is bound around a limb to stop temporarily the arterial blood supply and so control severe bleeding. Tourniquets should be applied with caution; unless untied within 15 minutes, GANGRENE may result, necessitating AMPUTATION. Because of this serious hazard, they are rarely used nowadays; direct pressure on the bleeding points is simpler, safer and equally effective in emergencies. A temporary tourniquet to an arm to increase the distension of veins when taking a sample of blood does no harm.