The severity of burns is closely related to the time that the causative agent acts on the body, the longer the time, the deeper the burns. Therefore, the scene rescue to race to quickly get away from the source of injury, effective on-site first aid is possible to reduce the injury, commonly used methods are as follows: 1, flame burns clothes on fire, quickly take off the burning clothes, or lying down on the ground to roll to extinguish the flame, or water, live with clothes, quilts and other things to put out the fire. Do not stand and shout or run to call for help, to prevent head, face and respiratory burns; 2, hot liquid burns immediately remove the hot liquid-soaked clothing; 3, chemical burns chemical substances of many kinds, common acids, alkalis, phosphorus, etc.. When the chemical substances in contact with the skin, the injury-causing effect and the concentration of these substances, the time of action related. Generally speaking, the higher the concentration, the longer the action time, the more serious injury to the body. Therefore, after the injury, you should first remove the clothing soaked with chemical substances, and immediately rinse with a large amount of water to remove the chemical substances from the trauma as much as possible (generally not less than 30 minutes). Cold therapy Cold therapy can not only reduce the residual heat of the trauma surface to continue to damage the trauma surface still alive tissue, but also can reduce the tissue metabolism of the trauma surface, is the local vasoconstriction, exudation is reduced, thus reducing the trauma surface edema, and has a good pain relief effect. The common method is to rinse with plenty of tap water or clean river or pond water immediately after the injury, for no less than 30 minutes. Protection of burn wounds After the patient is removed from the scene, attention should be paid to the protection of the burn wounds to prevent recontamination. Do not apply colored drugs except for very small traumas, so as not to affect the judgment of the injury and debridement in the subsequent treatment. For second-degree burns blisters are generally not removed.