Fever is a common clinical symptom, and many people regard it as the culprit, and will not stop until they see “fever”, and try all means to reduce it. The purpose of fever is to increase the inflammatory response, inhibit the growth of pathogenic microorganisms of bacteria and viruses, and create a pathophysiological environment that is not conducive to the development of infection or other diseases. The clinical level of fever should not be used to measure the severity of the disease, but in a sense the level of fever reflects the body’s ability to defend against emergencies. However, excessive fever can have adverse effects on the body, especially when the body temperature is >42℃, which often indicates that the patient is in serious condition and active measures should be taken to avoid tissue damage caused by high fever. For infectious fever, based on the etiological treatment of Western medicine, our department divides fever into two categories: external fever and internal fever, according to the etiological mechanism of fever. We often achieve unexpected results.