A cold with a persistent temperature of 37.3 to 37.5 degrees is considered a low-grade fever, which may be caused by a low immune system, a persistent low-grade fever due to viral invasion of the body, or other illnesses that can cause a low-grade fever. When you have a cold, pathogenic bacteria enter the body, causing an inflammatory response, the body will carry out a series of immune-inflammatory response to the pathogenic bacteria, the inflammatory response will produce endogenous pyrogens, pathogenic bacteria are exogenous pyrogens, resulting in an upward shift of the body temperature regulating point, there is an increase in heat production and a decrease in heat dissipation, resulting in an elevation of body temperature. In addition, one should be alert to the presence of comorbidities with other diseases that can cause low-grade fever, such as rheumatologic-immunologic diseases. If symptoms worsen, prompt medical attention should be sought. Please follow your doctor’s instructions for medication.