Children 39 degrees fever one night, if the mental state is good, no drowsiness, vomiting, convulsions, urinary and so on, generally not a big problem, if the mental state is poor, drowsiness, chills, vomiting, diarrhea, headache, urinary, or even convulsions, the condition is more serious. When viruses, bacteria and other pathogenic bacteria enter the human body, the pyrogen it produces will cause fever in the human body, therefore, fever is an important clinical manifestation in the process of disease progression. If the child’s mental state is good during the fever process, it suggests that the disease is relatively stable and generally not a big problem. If the child is drowsy, has chills, headache, severe crying and poor mental status, the condition is more critical. When the child has a high fever, parents should timely physical cooling, oral ibuprofen and other antipyretic drugs if necessary, and timely pediatric consultation, to clarify the cause of the disease, to take targeted treatment, so as not to delay the condition.