The body temperature of normal children can fluctuate in a certain range, generally speaking, the normal axillary temperature is 36-37℃. Exercise, after eating, crying or entering a hot environment can make the body temperature slightly increase temporarily. Fever is a normal defense reaction of the body, but excessive fever or long-term fever can involve various regulatory functions of the body, such as high fever causes increased neuroexcitability and even convulsions; ultra-high fever leads to central inhibition and coma; fever can also lead to increased catabolism, excessive vitamin consumption, reduced secretion of digestive juices, reduced digestive enzyme activity, increased destruction of their own proteins, making the child wasted and weak. 1, etiology The causes of fever in children are complex and often require a certain period of observation and reference to the necessary laboratory tests to make a clear diagnosis. The most common causes are infectious diseases, including bacteria, viruses, mycoplasma, rickettsia, spirochetes, parasites, etc.; non-infectious diseases such as rheumatic diseases, allergic reactions, heat stroke, hyperthyroidism, leukemia, malignant tumors, etc. 2.Treatment The treatment of pediatric fever is first to remove the cause, and then symptomatic treatment. Physical cooling is preferred for children with high fever, such as alcohol baths, cold and wet compresses, warm baths, etc., followed by the appropriate use of antipyretic agents (see pediatric colds).