A baby with a temperature of 40℃ has a high fever that does not go away, it may be that the disease is in the acute stage, or because parents take the wrong way to reduce fever. 40℃ is a high fever, if there is no suitable antipyretic medicine at home, you can take the pediatrician directly to the hospital for intravenous infusion of antipyretic drugs or intramuscular injection, depending on the age of the child to give the treatment. If at home, oral antipyretic medication can be given or fever-reducing suppositories can be applied, and acetaminophen or ibuprofen can be applied. However, it is important to remember that the child’s temperature does not go down easily in a hyperthermic state, and physical cooling should be used within 1-2 hours of the application of antipyretic medication. Physical cooling can choose to apply antipyretic patches, or with warm water repeatedly wipe, or bathing and other ways to assist in fever reduction treatment, can play a very good fever reduction effect.