It is common for children to have fever, but many parents cannot see their children having fever, not only because there is a traditional concept that children’s fever will burn their brains, there is such a misunderstanding because medical knowledge is not yet popular and the reasons behind high fever are not clearly distinguished. Many diseases can cause fever, with different consequences for different diseases, and fever is only a manifestation of the disease, not its cause. Parents usually only see the common appearance of these diseases – fever – and ignore the cause of fever. In general, fever is a reaction of the body to a foreign substance, which in childhood is usually a pathogenic microorganism, i.e. an infection. The organism limits the reproduction of pathogenic microorganisms by fever, which should be a benign symptom for the organism. The vast majority of pediatric infections are of common endogenous origin, and the fever it causes rarely exceeds 41 degrees C. This type of fever does not cause damage to brain cells, leading to brain damage. As for fevers that may involve the brain, they are most often seen in diseases such as encephalitis, meningitis, sepsis, etc. that damage the brain parenchyma itself; or super high fevers that exceed 42 degrees Celsius, which can lead to irreversible heat degeneration of brain cell proteins, but such extreme heat is rarely accompanied by internal diseases.