Ice after injury to reduce swelling or hot compresses, mainly depends on the time of injury, both have the effect of reducing swelling, but the application of time is different. If the patient belongs to the injury within 48 hours of the swelling, this situation is mostly due to the tiny capillary rupture, bleeding, caused by swelling, at this time you can use ice and so on, through the cold compresses to make the rupture of the blood vessels contraction, reduce the bleeding and so on. If the injury is 48 hours later, you need to use hot compresses to reduce swelling, due to the injury 48 hours after the local tissue congestion and edema, this time the use of hot compresses and so on can promote the dissipation of bruises, reduce swelling. So choose to use ice to reduce swelling or hot compresses to reduce swelling, mainly depends on the time of injury, both have the effect of reducing swelling, only the application time is different. If the injury is within 24 hours, you need to use ice to reduce swelling, more than 48 hours, you need to use hot compresses to reduce swelling.