Fever refers to an increase in body temperature above normal body temperature, and is divided into infectious and non-infectious, while high fever is mostly a body temperature above 40℃. Persistent high fever is the most damaging to various organs and tissues of the body, especially the brain. If the body temperature is greater than 40-41℃, it can cause brain cell damage and brain edema, resulting in serious sequelae. If the fever is prolonged or persistently high, the metabolism of the body will be accelerated, oxygen consumption will increase, fat metabolism will be disrupted and acidosis will result; it can also promote the decomposition and consumption of its own proteins and lead to wasting and decreased resistance. High fever can also lead to dysfunction of cerebral cortex excitation and inhibition, reduced secretion of digestive juices, reduced vitality of digestive enzymes, gastrointestinal disorders, and a series of serious symptoms. Children with persistent high fever should be aware of the occurrence of febrile convulsions, which can cause abnormal brain discharge, brain cell hypoxia and edema, resulting in brain damage. Persistent high fever is usually due to the presence of certain inflammatory diseases or malignant tumors in the organism, so you should go to the hospital in time to identify the cause, actively reduce the fever and provide reasonable treatment for the cause to reduce the damage to the organism. The presence of persistent high fever is an alarm signal of the body and must be taken seriously. First of all, you should go to the hospital in time to clarify the cause of the disease and treat it for the cause. Secondly, you should pay attention to rest, drink more water, and actively use antipyretic drugs to reduce the damage of high fever to the body.