Normal body temperature is not a specific temperature point, but a temperature range. The body temperature deep in the body is relatively constant and uniform, which is called deep body temperature; while the temperature on the surface of the body is affected by many factors, with large changes and differences, which is called surface temperature. The body temperature referred to clinically refers to the average deep temperature. It is generally represented by the body temperature of the mouth, rectum and armpit, among which the rectal temperature is closest to the deep body temperature. Normal values: oral sublingual temperature is 37°C (range 36.2-37.2°C), rectal temperature is 37.5°C (higher than oral temperature (0.3-0.5°C), and axillary temperature is 36.5°C (range 36.0°C-37.0°C).