Generally, fever can be categorized into 4 degrees, low fever: 37.3-38 ℃, moderate fever: 38.1-39 ℃, high fever: 39-40 ℃, ultra-high fever: more than 40 ℃. 1. Hypothermia: refers to the body temperature in 37.3 ~ 38 ℃, the general body temperature in this range can first use physical cooling to normalize the body temperature, physical cooling effect is not good or the temperature has a tendency to further increase can consider taking cooling drugs (such as ibuprofen, etc.). 2. Moderate fever: refers to the body temperature in 38.1 ~ 39 ℃, generally when the body temperature rises to 38.5 ℃ or more, we should consider the use of drugs to lower the temperature. 3. High fever: refers to the body temperature of 39 ~ 40 ℃, when the body temperature is higher than 39 ℃ for a long time, may cause serious damage to the patient’s nervous system, so when the body temperature reaches 39 ℃ or more must be dealt with in a timely manner. 4. Ultra-high fever: refers to body temperature above 40℃, when the body temperature is higher than 40 degrees, it may cause permanent damage to the nervous system. It should be treated promptly.