A high fever of 39°C does not usually burn the brain. However, if the fever is caused by viral encephalitis or other brain diseases, it usually lasts for about half an hour may cause brain damage or abnormal brain function. Usually, a high fever of 39℃ will not cause brain damage, but physical cooling should be given promptly, such as ice packs or wiping the vascular-rich parts of the armpits, groin and neck with warm towels, while symptomatic treatment with antipyretic drugs, such as NSAIDs, can be given under the guidance of a doctor. If the fever is caused by viral encephalitis, epidemic encephalomyelitis, epidemic B encephalitis and other brain diseases, it may damage the brain function if it is not treated in time and lasts for about half an hour. In addition, if an infant has a high fever of 39°C, antipyretic drugs should be given promptly to prevent febrile convulsions, which may produce irreversible damage to brain cells. Patients with a high fever of 39℃ can drink more water, ensure adequate rest, avoid eating spicy and stimulating foods, and need to go to the hospital infection department or fever clinic as soon as possible if necessary.