A 3-month-old baby with a fever of 38.5 degrees needs to be given fever-reducing medicine immediately to reduce the fever. Because the child is too young, it is easy to have febrile convulsions, which can produce irreversible damage to the child’s brain cells. You can give the child oral ibuprofen suspension, and the specific dosage needs to be used according to the child’s weight in accordance with the instructions. In addition, the child should also be given physical cooling, you can use a warm towel to wipe the armpits, groin, neck and other places rich in large blood vessels, to help reduce the child’s fever. In addition, pay attention to the ventilation of the room and change the child’s sweaty and wet clothes and bedding in time to prevent secondary exposure to cold. We should treat the cause of the disease according to the child’s symptoms, for example, if the child has the symptoms of cold, you can give the child pediatric anilox granules, which need to be taken 3 times a day. If the child is too young, he or she needs to go to the hospital as soon as he or she appears to be in bad spirits.