Physical cooling is the local or systemic use of low temperature conduction and evaporation to bring down the body temperature. Normal pediatric body temperature is shown in the table below, and anything above the normal range is called fever. There are many factors affecting the body temperature, the common ones are eating (especially for infants and young children), movement, crying, too thick clothing, high ambient temperature can lead to an increase in body temperature; while hunger, less movement, poor warmth can lead to a decrease in body temperature. Physical cooling mainly includes two major methods, namely local cold compresses and whole-body cold therapy. Commonly used are ice bags, and ice capsules, the principle of contact conduction to achieve the purpose of cooling. The site of placement is often the child’s forehead or head, the ice capsule can be placed on the child’s body surface distribution of large blood vessels, such as the neck, axilla, groin, etc., pay attention to the child’s local skin color, such as pale, cyanosis and other conditions should immediately stop using cold to prevent impaired blood circulation or frostbite. 30 minutes later to measure the temperature and record, need to use cold for a long time should rest for an hour before repeated use, to give local tissue Recovery time. Warm water swabbing is a common way of whole-body cold therapy, the principle of which is that warm water contacting the skin increases the body’s heat dissipation through evaporation and conduction to achieve the purpose of cooling. Usually the basin can hold 32-34 ℃ warm water, before the swabbing bath will be placed on the head of ice bags, in order to prevent swabbing bath epidermal vasoconstriction, head congestion, aggravating the headache. The hot water bag is placed on the bottom of the foot to avoid chills and discomfort in the child. Loosen the end of the bed and the cover, but do not expose too much, take off the clothes, and spread the bath towel under the body.