The low fever of 37.4 ℃ after a cold that does not go away for several days is considered to be due to physiological reasons, secondary bacterial infections, complications of colds, and the presence of other diseases. 1. Physiological reasons: women’s physiological ovulation basal body temperature will rise, if at this time in the cold, it is easy to be mistaken for a low fever after a cold. 2. Secondary bacterial infection: a long cold may be complicated by bacterial infection, which can cause fever that does not go away. 3. Complications of colds: If colds are complicated by bronchitis or viral myocarditis, or rhinitis, sinusitis, otitis media, etc., low fever can also occur. 4. Other diseases: Fever is not necessarily related to colds, but may also be caused by other diseases, such as immune system diseases. If there is recurrent fever, it is recommended to go to the hospital, complete the examination, clarify the cause of the disease, and treat it under the guidance of the doctor, rather than blindly using medication by yourself.