Generally after ankle sprain, according to the degree of sprain, local cold compress can be applied within 24-48h in the early stage, and after 48h, local hot compress can be applied, but it is not absolute. If the swelling is obvious, you can extend the time of cold compress, cold compress can be extended to about 72h after you can take the way of hot compress. Cold compress is mainly to prevent excessive local swelling, cold stimulation can make vascular spasm, vascular spasm after the blood flow is reduced, blood flow can reduce the excessive local swelling. In addition, after the foot sprain, oral anti-swelling medications, such as Mizarin, should be taken to prevent excessive local swelling, and the affected limb should be elevated, which can promote blood return and reduce excessive local swelling.