In the clinical body temperature 31 ℃ is not normal. The normal axillary body temperature of human body is between 36-37℃. If the body temperature of human body is 31℃, the following reasons should be considered at this time: 1. It may be that the measuring thermometer is broken, the temperature measured at this time is not allowed, so this error may occur, you can change a thermometer to continue to retest the temperature. 2. If the body temperature is repeatedly measured at 31℃, you should go to the hospital immediately for consultation at this time. Consider hypothermia may lead to shock and other serious adverse consequences. 3, for some chronic diseases may also lead to hypothermia, should be treated with drugs under the doctor’s examination and diagnosis. 4, but the body temperature 31 ℃ is very rare, should find the cause of this situation caused by damage to the thermometer.