Fever is one of the most common symptoms in children and is also the most common cause of emergency care. Fever is a symptom, not a disease, and the cause behind the fever needs to be actively sought. When encountering a child with fever, it is crucial to assess the child’s condition in a timely manner and actively take appropriate diagnostic and treatment measures. 1, the definition of fever Fever refers to body temperature exceeds the upper limit of the normal temperature fluctuations in a day, clinical work is usually used axillary temperature ≥ 37.5 ℃ or anal temperature ≥ 38 ℃ defined as fever. 2, children’s body temperature measurement There are many ways to measure body temperature, such as anal temperature, oral temperature, axillary temperature, ear temperature, frontal temperature, in general, anal temperature is more accurate and reliable. Anal temperature: It is suitable for infants and young children, and the measurement result is accurate, but it is difficult for parents of children to accept, and the safety is not high. Oral temperature: measurement requires a period of oral closure, suitable for older children and adults, the measurement results are accurate, but the thermometer has the risk of being bitten off. Axillary temperature: the most traditional way, simple measurement, measurement to ensure accuracy, need to keep the child quiet, will dry the armpit sweat, measurement time is 5 minutes. Ear temperature: Infrared light is used to measure the temperature of the tympanic membrane in the ear, which has become more popular in recent years, but the accuracy of the measurement can be affected when there is more cerumen. Forehead temperature: forehead skin temperature is affected by the environment, the measurement results are not accurate. 3.Children’s fever gradation Low fever 37.5℃~38℃ Moderate fever 38.1℃~39℃ High fever 39.1℃~41℃ Super high fever 41℃ or more 4.Children’s fever causes The most common causes of fever in children are infectious diseases, such as bacterial infection, viral infection, etc. The most common sites of infection are respiratory system infection or digestive system infection. 5.Benefits of fever in children (1) When the body temperature rises to 38℃-40℃, it is not conducive to the growth and reproduction of bacteria and reduces the number of pathogens; (2) It accelerates the speed of chemical reactions in the body and improves the immunity and metabolic ability of the body; (3) Fever is an early symptom of many diseases and helps doctors diagnose diseases as early as possible. 6. When to seek medical attention for fever (1) temperature >38℃ for small infants <3 months; (2) temperature >40℃ for all children; (3) convulsions, drowsiness or irritability; (4) headache, abdominal pain, frequent vomiting or diarrhea; (5) unexplained rash; (6) children with underlying diseases, such as heart disease, immune system deficiency, systemic lupus erythematosus, kidney disease, etc.; 7. Treatment of fever in children (1) physical cooling: Caution, domestic guidelines are not recommended; (2) antipyretic drugs acetaminophen: for ≥ 2 months and adults, 10-15mg/Kg. times, 4-6 hours can be repeated; ibuprofen: for ≥ 6 months and adults, 5-10mg/Kg. times, 6-8 hours can be repeated. The purpose of antipyretic in children is to improve the comfort of the child, antipyretic drugs are not recommended for short time repeated use, easy to cause drug toxic side effects, occurrence of liver and kidney function damage; acetaminophen and ibuprofen combined application is not recommended; glucocorticoids are not recommended for antipyretic in children; antipyretic drugs can not effectively prevent the onset of convulsions.