Fever and body aches after a cold are due to a decrease in the body’s immunity and infection by viruses, bacteria, mycoplasma and chlamydia, which cause a significant inflammatory reaction in the mucous membrane of the upper respiratory tract. At this time, the systemic immune response is relatively strong, the metabolism of the body is relatively accelerated, the inflammatory response will gradually increase the body temperature, the fever will also promote the metabolism to increase, the oxygen consumption of the body is relatively enhanced, and a state of hypoxia may occur. At this time, the body will undergo anaerobic metabolism, producing large amounts of lactic acid and so on. In addition, there are metabolites of inflammatory reactions and inflammatory factors that stimulate the body’s nervous system, resulting in painful symptoms throughout the body. Symptomatic treatment, such as ibuprofen and acetaminophen, can be given clinically.