A baby’s body temperature of 37℃ is normal. A baby’s underarm temperature is normally 36-37℃, anal temperature, also known as rectal temperature, is normally 36.5-37.5℃, and oral temperature, also known as sublingual temperature, is usually 0.2-0.5℃ higher than the underarm temperature. The anal temperature best reflects the true temperature of the body, but because the axillary temperature is easy to measure, it is easily accepted. Fever is defined as an axillary temperature ≥37.5°C and an anal temperature ≥38°C that fluctuates more than 1°C during the day. The degree of fever is usually judged according to the axillary temperature, axillary temperature <38 ℃ for low fever, 38-39 ℃ for moderate fever, 39-41 ℃ for high fever, greater than 41 ℃ for ultra-high fever. It should be noted that the temperature does not represent the severity of the disease.