Colds and chills are mainly due to the invasion of foreign pathogens (viruses) and the entry of foreign pyrogens into the blood circulation, which act on the body temperature center, resulting in an upward shift of the thermoregulatory point and a consequent feeling of coldness. Colds generally refer to the typical symptoms presented by upper respiratory tract infections (cough, runny nose, nasal congestion, fever, etc.). Common pathogens are viruses, including parainfluenza virus, adenovirus, and respiratory syncytial virus. These viruses themselves act as a thermogenic source in the body temperature center, causing a shift upward (e.g., 38.5°C) of the thermoregulation point to be followed by a normal body temperature (37°C) that is lower than the thermoregulation point, making the person feel cold. In addition, these foreign pathogens will cause the body to produce an immune response and inflammatory response, and the inflammatory mediators produced (such as prostaglandins, interleukin-1, etc.) can also lead to fever. In the case of a cold, the body feels cold soon after the fever, you should seek medical attention in a timely manner, under the guidance of a physician to diagnose and treat.