There is no optimal treatment for a four-year-old baby with a fever of 39°C. Physical cooling and oral antipyretic medication can be used to drive the body temperature down, but it is also important to treat the cause of the fever. Fever is a common symptom of childhood, for children with fever body temperature back to normal fast and slow with the state of the disease and choose the right way to reduce fever, there is no best way to reduce fever. A four-year-old baby with a fever of 39 ℃ can use warm water on the child’s forehead, reduce the wearing of clothing and other physical cooling methods to lower the temperature, and encourage the child to drink more water. Also need to use antipyretic drugs such as ibuprofen, acetaminophen and other antipyretic treatment under the guidance of a doctor. At the same time, the treatment of the cause of the disease is also very important for the recovery of body temperature, such as respiratory tract infections caused by bacterial infections, need to actively use antibacterial drugs such as cefaclor, cefdinir and other anti-infective treatment. All of the above drugs need to be used under the guidance of a doctor, avoid self-medication. When a baby is four years old with a fever of 39 degrees, he should go to the hospital in time to be evaluated and treated by a specialist.