Baby fever to 39 degrees already belongs to high fever, if the fever does not go down overnight and is caused by encephalitis, it may burn the child’s brain, which will cause some damage to the child’s intelligence, as well as tinnitus, deafness, convulsions, affect vision and other problems. Therefore, parents must actively help their children to lower their temperature. If the baby’s body temperature has exceeded 39 degrees, it proves that the condition is more serious, and if it is not immediately treated to lower the temperature, it is likely to cause some unfavorable conditions to appear. Therefore, when the fever is 39 degrees is not recommended to carry overnight, to give the child timely antipyretic drugs, and with physical cooling. At the same time, go to the hospital to check to understand the reason why the baby has a high fever that does not go away, and treat the cause of the disease in order to achieve good treatment results. During the period of fever reduction treatment, parents should pay attention to actively replenish the baby’s fluids to prevent dehydration and metabolic disorders, drink more water, and pay attention to keeping warm to avoid catching a cold again.