Fever is the most common symptom in children, and parents’ excessive fear and anxiety about their children’s fever is very common. In the pediatric clinical work for many years, we often encounter parents holding their children to the doctor because of fever, indiscriminately asking the doctor to give the child a fever-reducing injection, and anxious when the fever does not go down in 10 minutes, and some parents even rush to the hospital several times a day when the child has a fever, urgently asking to “reduce the fever as soon as possible”. This phenomenon is called “fever phobia” abroad. What should we know about fever? Fever is both beneficial and harmful to the body. In fact, fever is a defensive response of the body to external stimuli (most often infection), and its initial purpose is to kill the invader. However, excessive fever does cause discomfort, especially in children, because the nervous system is not mature enough and excitement can easily generalize, sometimes even causing convulsions, i.e., hyperthermia, so excessive fever should really be avoided and can be reduced by medication or physical methods. How high is a fever? What is considered a high fever? The human body is regulated by the biological clock, and the body temperature is also included in this regulation, so the normal human body temperature fluctuates 24 hours a day, with the lowest temperature in the early morning and the highest temperature at 3 or 4 o’clock in the afternoon. Body temperature above 37.4℃ is considered fever, 37.4℃~38℃ is low fever, 38℃~39℃ is medium fever, and above 39℃ is high fever. Infants and young children are at high risk of high fever. However, infants and children are more able to tolerate fever than adults, so it is recommended to use antipyretic drugs only when the temperature of children is 38.5℃ or higher. There is no basis for thinking that a fever will “burn the child silly”. Unless the child is suffering from severe encephalitis, or the fever is caused by “muffled fever syndrome”, a fever below 40℃ will not affect the brain much as long as the child is actively cooled down and convulsions are avoided. How should we deal with fever? 1, any degree of fever should first reduce clothing and cover, clothing, cover too much, hinder the distribution of heat and evaporation, not beneficial to reduce fever; secondly, we should drink more water, drinking water can supplement the evaporation of water due to fever, sweating after drinking water, the evaporation of water, can help reduce fever. In addition, increased urination can also take away some of the heat and accelerate fever reduction. 2.Physical cooling: When the body temperature is lower than 38.5℃, physical cooling is the preferred antipyretic measure. Ice or cold water (or cooling paste) can be used on the head and neck, armpits and bilateral groin. Also can be used about 30 ℃ warm water bath, with the evaporation of water and take away heat, is also a fairly simple method of reducing fever. When the effectiveness of physical cooling is not good, you can choose the appropriate antipyretic drugs under the guidance of a doctor. 3.Application of antipyretic drugs to reduce fever. When the body temperature is higher than 38.5 ℃, you need to choose drugs to reduce fever. If there is a history of high fever convulsions or family history, in addition to the application of antipyretic drugs, oral convulsion prevention drugs (such as phenobarbital) are required if necessary.