Infants with body temperature over 37.4℃ are considered to have fever, 37.5℃-38℃ is low fever, 38.1-39℃ is moderate fever, 39.1-40℃ is high fever, and over 41℃ is super high fever. To determine whether an infant has a fever, the body temperature of the mouth, armpit and anus is usually measured, generally the mouth temperature is higher than 37.3℃, the armpit temperature is higher than 37.4℃ and the anus temperature is higher than 37.8℃. The body temperature of infants is easily affected by the external environment, such as wearing too many clothes, insufficient water intake, lack of air circulation in the room, before and after strenuous exercise, and preventive injections. If the body temperature is lower than 38.5℃, you can drink more boiled water or apply physical methods to lower the temperature; if the body temperature exceeds 38.5℃, it is recommended to use antipyretic drugs under the guidance of a pediatrician. When measuring body temperature, it is recommended to prefer axillary temperature. If you use mercury thermometer, you need to shake the mercury column to below 36℃ and clip it for more than 5 minutes for measurement.