There are several factors that usually lead to fever: 1. From the perspective of Chinese medicine, it is caused by fire, usually liver fire, lung fire and heart fire or upper jiao fire, hyperactive liver yang, and excessive deficiency of kidney qi, which cause the body to feel hot, but not fever. 2. The clinical symptom of fever can also be found in diseases with hyperfunction, such as hyperthyroidism and hyperadrenocorticism, which also have the above clinical symptom. 4. In cases of trauma or brain damage, or major brain impact, the hypothalamic nerve center can also have this symptom when the trauma causes the upward shift of its own heat-sensitive neurons.