Everyone’s normal body temperature is not exactly the same, and the same person’s body temperature varies throughout the day. The normal body temperature for children is 36 to 37°C measured in the armpit. If the armpit temperature is greater than or equal to 37.5°C, while fluctuating more than one degree during the day, it means that the child has a fever. Most acute fevers in babies are caused by infections, the majority of which are respiratory viral or gastrointestinal viral infections, followed by bacterial infections. That is, when a baby has these diseases is feverish, so in this case, it is important to monitor the child’s temperature every 4-6 hours, especially when the child is found to be flushed, irritable and crying, with cold hands and feet, be sure to use a thermometer to measure the child’s temperature to see if the child has a fever. In summer, babies are prone to heat stroke because of the heat, so it is also important to monitor the child’s body temperature regularly. It is also important to monitor the temperature of the child 24 hours after vaccination, and to provide early symptomatic treatment for fever. Some chronic diseases can cause persistent fever in children, such as juvenile rheumatoid arthritis, inflammatory bowel disease, lymphoma, and hereditary periodic fever. For children with these diseases, it is also important to monitor the temperature regularly. Babies with fever, if low fever, usually do not affect mental status, so when a child has a respiratory or digestive disease, parents should take the temperature proactively to detect the fever in time to actively deal with it.