In case of axillary temperature, the normal value is below 37.0°C, sublingual temperature is below 37.2°C, and the normal value of rectal temperature is 37.7°C or below. Rectal temperature is the temperature closest to the human body, in 37.0-38.0 ℃ belongs to mild fever, 38.0-39.0 ℃ belongs to moderate fever, 39.0 ℃ or more belongs to high fever. The body temperature is relatively constant, generally less affected by the outside world, the difference will not exceed 1 ℃. Under physiological conditions, such as exercise, eating, drinking hot and cold water, bathing or before and after a woman’s menstrual period, body temperature may fluctuate. Elderly people have relatively low body temperatures and children have slightly higher body temperatures.