A tourniquet is a tight fabric band that compresses a bleeding artery to try to stop blood from flowing. Tourniquets should be used only after other methods of stopping bleeding are tried first. A tourniquet should not be used at all unless the bleeding is heavy and life-threatening.
The reason tourniquets should be used rarely if at all is that a limb may need to be amputated if the tourniquet is left on too long. In some military situations, the wounded person's forehead is marked to indicate the time the tourniquet was applied. Ink or blood may be used to mark the forehead.
Before the use of a tourniquet is even considered, the direct pressure method should be used. A clean cloth is placed over the bleeding wound and the palm of the hand is pressed down to help limit blood flow without totally stopping blood circulation. Another way to try and stop bleeding from a wound before resorting to a tourniquet is to raise the wound higher than the heart. This should be done while applying direct pressure on the wound.
If the bleeding remains uncontrolled, shock may result. Shock occurs when the blood supply to the brain and other organs is restricted. Death is a very real outcome of shock from bleeding. If other methods to stop life-threatening bleeding won't work, then a tourniquet is used.
A tourniquet is wrapped around the wounded limb and then secured with some type of stick object positioned so that the cloth can be twisted tightly and held in place. Once tightened, the tourniquet should not be loosened until it is removed altogether. The tourniquet should be left on only until the bleeding stops because otherwise serious damage to the limb could occur. Fabric with some stretch to it, such as linen, is usually used for tourniquets, but other cloth such as toweling may also be used. If the blood soaks through the first layer of cloth, that layer of material should still remain on for the time that the tourniquet is worn to allow clotting to occur.