Hot compresses for sprains are usually carried out 24 hours after the sprain, which can increase local blood circulation, effectively promote the metabolism of local inflammatory metabolites, reduce inflammatory edema, and reduce pain. And through hot compress, can make the injury site of the muscle, ligament, tendon in a relaxed state, help its recovery. After increasing blood circulation, the metabolism and nutrition of the sprained part can be effectively ensured, and the recovery speed is faster than normal. But not immediately after the sprain hot compress, because after the sprain small blood vessels will have rupture, hot compress will lead to further increase the rupture bleeding, resulting in further aggravation of swelling, is not conducive to the healing of the injury location. In addition, the injury should be immediately after the cold compress, because the cold compress can lead to blood vessel rupture coagulation hemostasis, to avoid further increase in swelling.