Whether or not ice can reduce swelling needs to be determined by the cause of the lump and cannot be generalized. If the edema is caused by mosquito bites, burns, soft tissue contusions such as sprains and falls caused by trauma or inflammation such as fractures, ice can be used to reduce the swelling within 24 hours of the injury. Due to thermal expansion and contraction, ice can make the injured blood vessels occlusion, so that edema and bleeding reduced; if the edema is caused by varicose veins, heart and lung diseases, can not be reduced by ice, need to be diagnosed according to the symptomatic treatment. It is better not to apply ice for more than 10 minutes each time, and it is not advisable to apply ice for more than 24 hours after the injury, and it is necessary to switch to hot compress to accelerate the blood circulation, so as to activate blood circulation and promote the absorption of blood stasis.