Physical hypothermia is a method of lowering body temperature by local or systemic low-temperature conduction and evaporation. There are many factors affecting body temperature, some of which are eating (especially for infants and young children), exercising, crying, over-thickness of clothing, and high ambient temperature, all of which can lead to an increase in body temperature; while starvation, little movement, and poor warmth can lead to a decrease in body temperature. Therefore, it is important to note that the temperature should be taken when the child is calm. If the child is exercising or crying, or after a meal, the temperature should be taken after 30 minutes of calmness. Physical cooling mainly includes two major methods, i.e. local cold compresses and systemic cold therapy. 1, local cold compresses commonly used cold water bag (with rubber gloves or balloons, filled with cold water or room temperature water can be), ice bag, ice capsule, the principle is to achieve the purpose of cooling through contact conduction. Place the part of the child’s forehead or the top of the head, cold water bag and ice capsule can be placed in the distribution of large blood vessels on the surface of the child’s body, such as the neck, armpits, groin, etc., pay attention to the observation of the child’s local skin color, such as pallor, cyanosis, etc. should be immediately discontinued, to prevent the occurrence of blood circulation disorders or frostbite. 30 minutes after the measurement of the body temperature and record, need to be long time cold should be rested for an hour and then reuse, to give with the local tissue recovery time. Local tissue recovery time. Some parents put antipyretic patches on the palms and feet of their children, and this method of reducing fever is wrong. When the child is feverish, his peripheral circulation is poor, and thus the phenomenon of “hot body, cold hands and feet, chills and discomfort” occurs. Therefore, it is not possible to apply cold compresses to the palms and feet when you have a fever. 2, warm water swabbing Warm water swabbing is a commonly used way of whole-body cold therapy, the principle of warm water in contact with the skin, through evaporation, conduction to increase the body heat dissipation, to achieve the purpose of cooling. Usually the basin can be 32-34 ℃ warm water, loose the end of the bed and cover, but not too much exposure, take off your clothes, bath towel under the body. Will be soaked towel wrung to half dry, wrapped in the operator’s hands, to centrifugal direction pat. The upper limbs, lower limbs, and back are patted separately, and each limb or back is swabbed for 3 minutes, with the whole process taking no more than 20 minutes. Armpit, groin is a large blood vessels through the place, to extend the time of swabbing, prohibit swabbing the chest area, abdomen, neck, feet and other parts of the heart, so as not to cause adverse reactions. After swabbing with a large towel to dry the skin, half an hour later to re-measure the body temperature. Because fever can increase the skin’s unnoticeable water loss, usually every 1 ℃, every 24 hours more water consumption of about 13 ml / kg. Therefore, in addition to the above two methods, a small amount of drinking sugar and salt water can be a better supplement to the increase in the unnoticeable water loss due to fever, which is more conducive to the recovery of the body temperature. In addition, after oral antipyretics, it usually takes 40-60 minutes for them to take effect. Children with fever need to be closely monitored for changes in their condition.