Cold and fever is mainly due to the lowering of the local defense function of the respiratory tract, the immune function decreases after the infection of the virus caused. Common cold is a kind of acute upper respiratory tract infection, common cold is caused by viral infection, the human body in the rain, sudden changes in climate, overwork and other factors, the immune function will decline, the body of the original virus or direct contact with the virus carriers, resulting in rapid reproduction of the virus in the body, a serious cold can cause fever, chills, headache and so on. Influenza, or flu for short, is a respiratory infectious disease caused by the influenza virus, which can cause high fever, headache, fatigue and other toxic symptoms. Although colds and fever are relatively common, it is recommended to seek timely medical treatment if necessary, and usually pay attention to exercise, maintain a regular routine, increase the body’s immunity, can effectively prevent colds.