In the acute sprain within 24 hours is not recommended for hot compresses, generally recommended ice, because during this period the sprained tissue microvascular rupture, will cause local bleeding, this time ice can make vasoconstriction, reduce local bleeding, reduce swelling. If this time hot compress, will cause vasodilation, will cause a large amount of blood flow to the sprained part, will accelerate the swelling, but also cause acute pain. When after 24 hours, basically has reached the situation of hemostasis, this time you can start hot compress, at this time vasodilatation, can take away the local inflammatory factors and pain factors, to achieve the effect of symptom relief.