Have the person lie down and find out where the blood is coming from. [substeps] Tourniquets only work on limb injuries, not trauma to the head or torso.
[header] How to apply a tourniquet [title] Discover where the blood is coming from. [step] If you find yourself in an emergency situation where someone (or an animal) is severely injured and bleeding, approach with confidence and reassurance. Helping someone in a life-threatening situation is brave, but you must try to discover and assess the injury as quickly as you can.