Ice packs to reduce swelling are usually applied every 2 hours for no more than 20 minutes at a time. When the body is swollen due to trauma and other causes of muscle swelling, ice packs can achieve a certain reduction in swelling. Ice should be careful not to ice bags and other cold objects in direct contact with the skin, it is recommended to use a towel wrapped in the surface of the cold object, and then placed on the injury for ice to reduce swelling. Ice can slow down the local blood flow, can reduce the accumulation of bruises caused by redness and swelling. Ice can not be too long, may lead to local blood flow or even frostbite, it is best to ice every 2 hours, each time the ice about 20 minutes, can achieve a better effect of swelling, and at the same time will not cause damage to the body or cause discomfort.