The recurrence of low fever and high fever may be related to mental factors, infectious factors, tumor factors and so on. 1. Mental factors: if the patient is in a state of long-term emotional suppression, depression, physical and mental fatigue may cause the patient to develop autonomic nervous system dysfunction, endocrine disorders, some patients may have a low fever and high fever repeatedly. 2. Infectious factors: when patients have tuberculosis, viral bronchitis, cholecystitis and other diseases, various pathogens can stimulate the immune system to produce endogenous thermogenesis on the thermoregulatory center to cause significant impact, may appear low fever and high fever recurrence. 3. Tumor factor: when patients have various malignant tumors such as liver cancer, lung cancer, stomach cancer and other malignant tumor-occupying diseases, local tissue necrosis of the tumor may also appear to absorb heat, which may lead to recurrent episodes of low-fever and high-fever. Recurrent episodes of low fever and high fever may also be caused by other reasons, so it is recommended to consult doctor in time, clarify the cause of disease and follow the doctor’s instruction for active treatment.