If a 3-year-old child has a fever of 40℃, it can be treated with antipyretics, including oral antipyretics and antipyretic suppositories, of which the acetaminophen component and ibuprofen component are relatively safe. When a 3-year-old baby has a fever of 40℃, timely symptomatic treatment is necessary to avoid febrile convulsions caused by elevated body temperature. In addition to the application of antipyretics, more warm boiled water should be consumed to avoid a large loss of water resulting in insufficient amount of circulating fluid, which can cause a persistent high fever that does not drop. Physical cooling can also be chosen. The baby will cause a lot of sweating after the medication, and the baby’s care should be strengthened by drying the body with a dry towel and avoiding excessive ventilation, while the cause of the fever should be actively sought, treated for etiology and dealt with in a timely manner.