The normal axillary body temperature in children is generally 36 to 37°C. However, due to poor thermoregulation in children, body temperature can fluctuate within a certain range. Short-term temperature fluctuations, but children eat, sleep and play are normal, no uncomfortable feeling, is not a pathology. Fever is a symptom of many pediatric diseases and a reflexive response to disease. It is the body’s defensive response to infection, stimulating the body’s anti-disease and detoxification function, resisting the attack of germs and promoting recovery. The level of fever is not necessarily parallel to the severity of the disease. If an infant suffers from a cold or an early childhood rash, the body temperature may suddenly rise to about 40℃, but the child is generally in a better condition and recovers more quickly after the fever subsides; weaker newborns and children with serious diseases may not have a higher body temperature, and their defenses against disease are poorer. Therefore, it is important to pay attention to both the degree of fever and the mental state and general condition of the feverish child. If the fever is accompanied by poor mental health, attention should be paid. If the fever is only high and the other conditions are good, there is no need to visit the doctor several times. If the fever drops and the child’s condition improves, this is a normal fever reduction. If the temperature drops suddenly and the condition worsens instead of improving, it is a sign of critical condition and should be seen promptly.