Head knocked big bag can follow the doctor’s instructions ice pack for 30 to 40 minutes. Ice compresses reduce the local temperature of the body surface, make the subcutaneous peripheral blood vessel contraction, reduce blood flow, reduce the permeability of blood vessels, thus reducing further bruising and fluid exudation, and alleviate bleeding and swelling. In addition, cold compresses can somehow “paralyze” the nerve endings of “pain”, reduce muscle spasm, avoid secondary injury to tissue cells, temporarily slow down the local nerve conduction velocity, and play the effect of pain relief. The head knocked a big bag in the head within 24 hours for ice, but pay attention to the ice outside to wrap the towel, so as not to be too low temperature, time should not be too long, to prevent hypothermia injury. Use two towels soaked in cold water and wrung out alternating cold compresses, 2 to 3 minutes to change the towel, for 30 to 40 minutes. It should be noted that the first 2 hours after the injury, must maintain close observation, if there is unconsciousness, impaired movement of the hands and feet and other conditions appear, immediately seek medical attention.