Usually a simple fever of 40℃ has no effect on the brain and will not cause damage to the body, but accompanied by intracranial infections, high fever convulsions, etc., may damage brain cells and need to be given active treatment. The basic component of brain cells is protein, which is usually gradually destroyed above 42℃. If it is just a simple fever with a body temperature of 40℃, it is a high fever and will not cause damage to the brain. If the fever is caused by encephalitis or meningitis, it is easy to affect the normal metabolism and function of brain cells, which may induce convulsions and cause hyperthermia, resulting in changes such as functional damage of brain cells, which has a greater impact on patients. Therefore, the cause of the disease needs to be clarified and actively treated, with oral administration of ibuprofen and other drugs to control the body temperature, drinking more water, and physical cooling. If the patient’s temperature remains high, treatment should be given at a fever clinic or internal medicine department without delaying the condition.