If a baby has a fever of 40 degrees, the brain is usually not damaged if the fever is simple and is reduced in time. If the fever is persistent or has an infectious disease inside the skull, etc., it may have an effect on the brain. A high fever of 40 degrees is a very high temperature for a child, but if the fever is only simple and the fever is reduced in time, the child’s body temperature can usually come down very quickly, which usually does not affect the central nervous system too much, and therefore will not burn the brain. If the baby persistent high fever, due to this stage of the nervous system is not fully developed, it is easy to high fever convulsions (due to high fever caused by convulsions convulsions), and easy to cause damage to the central nervous system, thus burning the brain, but if the active treatment, some children can recover. Some babies with high fever is caused by intracranial infectious diseases, such as meningitis, encephalitis, etc., if you do not take timely treatment, it is likely to lead to brain cell and nerve function damage, and often lead to sequelae. Babies with a high fever of 40 degrees must be timely cooling treatment, and go to the hospital, identify the cause and cooperate with the doctor’s treatment.