Once the sprained foot, many people will first use a cold compress to reduce the swelling of the injury, and soon switch to hot compresses or hot water to promote wound healing. In fact, this practice is wrong. Modern medicine believes that, unless there are special circumstances, otherwise, after the injury, at least the first 48 hours should be treated with a cold compress rather than with heating. The effect of ice is to reduce the blood flow to the injury, so that internal bleeding and swelling at the injury site can be controlled, and the recovery process will be accelerated. Why can’t you use heat for the first two days after the injury? Because if the temperature of the injured area is high, it will increase the blood flow to the injured area and make the swelling and pain of the injured area increase. If the injury has a small blood vessel rupture, it will increase the amount of bleeding, making it difficult to absorb the hematoma and slow down the recovery process. So, how to apply cold compresses? Generally in the first two days after the injury, every two hours to use ice bags for 10 to 20 minutes, ice bags and skin with a towel, bandages and other things to separate. In addition to cold compresses, the early stages of injury, but also to do three things: first of all, to let the injury rest, do not move. Secondly, the injury should be properly wrapped up, which can also relieve swelling. Thirdly, the injured area should be properly elevated, slightly higher than the heart area, to reduce local blood flow. When the swelling of the injured area is controlled and begins to subside, then apply warm compresses, which can dilate the local blood vessels and promote the absorption of the hematoma.