Usually there are two types of fever, one is active fever of the organism and the other is passive fever of the organism. Active fever is the most common form of fever in children, for example, when children are infected with inflammatory diseases (most often the flu), when the body’s active fever is aimed at defeating the inflammation. The hypothalamus of the human brain controls the regulation of body temperature, and the body temperature does not usually exceed 40.5°C when the fever is active. So if the fever is not reduced in time, the body temperature will keep rising? Fact: This is wrong. There is a thermostat in the brain, so a fever caused by an infection will often peak at 39.5-40°C, and rarely exceed 40.6-41.1°C. Passive fever is caused by external causes such as heatstroke, poisoning, traumatic brain injury, tumors, etc. that lead to problems in the regulatory center of the brain, when the temperature tends to reach above 40°C. In fact, only ultra-high fever, like 42°C or higher, can cause brain damage, and in reality children generally do not have fevers that can reach this temperature, but only when the body is under extreme environmental temperatures, the body temperature will be high to this extent (such as locking the child in a closed car on a hot day). The fever can sometimes cause varying degrees of abnormality in consciousness. It is generally said that fevers that burn children’s brains out are due to diseases such as encephalitis and meningitis, and that fever is only one of the symptoms of these diseases, but what really affects the brain is a serious brain infection. Fever does not burn the brain, and the higher the fever, the more serious the problem. 6 months of age and older should not use the height of the fever temperature alone to predict or judge the cause of the fever or the severity of the problem, but a temperature of ≥38°C in small infants <3 months of age or ≥39°C in infants 3-6 months of age suggests the possibility of a serious bacterial infection or a serious problem. Remember, fever is not always a bad thing, it can help your child get rid of an infection.