The causes of fever in the second half of the night include infectious factors and autonomic nerve disorders. 1. Infectious factors: mostly due to viral infections, bacterial infections, mycoplasma infections and other causes of fever in the second half of the night. Some viral infections are self-limiting diseases, which are treated symptomatically with fever-reducing drugs; bacterial infections and mycoplasma infections need to be treated with cephalosporin antibiotics, macrolide antibiotics and other anti-infective treatments. 2. Autonomic disorders: children are frightened in the middle of the night, sleep disturbances, crying, etc., will cause autonomic dysfunction, usually manifested as low fever symptoms, body temperature is generally not more than 38 degrees Celsius. Children in the second half of the night fever, there may also be other causes, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment, the above medication as prescribed by the doctor.