A low fever after a headache with a high fever may be due to the recovery period of the disease as well as the low fever after infection. 1. In the recovery period of the disease: usually for the cause of the disease to take effective treatment, if already play a therapeutic effect, the body temperature will change from high to low, and then gradually return to normal, can be seen in the viral, bacterial, and a variety of pathogenic microbial infections, usually in this stage of the body temperature has been improved, so there will be a headache after high fever fever low fever situation. 2. low fever after infection: this low fever time is relatively long, the early stage of a clear infection, the late persistent low fever, some patients can last several weeks, or even months of time, this case of low fever lasts for a long time, the body temperature is not very high, at 37.5 ℃, seldom more than 38 ℃, and therefore there will be a headache with high fever after low fever. If the patient has a headache with high fever and low fever, it is recommended to consult a doctor in time, after a clear examination, according to the doctor’s instructions for treatment.