In autumn, it gradually gets cold, the day-night and indoor-outdoor temperature differences are great, and the air is dry. The respiratory mucosa is constantly stimulated by the sudden cold and sudden warmth, which weakens the body's defenses against disease and provides the pathogenic organisms with an opportunity to exploit. The cold and other upper respiratory infections are of high incidence in autumn. The most terrible cold is “influenza”, which is characterized by acute onset, short latency, high infectivity, and obvious symptoms including high fever, headache, running nose and limb pain. Some influenza may be accompanied by pneumonia. Therefore, it is necessary to take more exercise and appropriate precautions in winter, especially for the elderly and children.