Yang qi in traditional Chinese medicine mainly refers to the functions of body temperature warming and exercise. Yang deficiency refers to the deficiency of the function and vitality of human viscera, and the decline of warming function, resulting in the syndrome of aversion to cold and preference for warmth. Therefore, such people are usually afraid of cold and prefer heat or hypothermia. They are resistant to summer but not winter, and like to eat warm food. It is also sensitive to the cold and dampness of the outside world, and it is easy to get frostbite in winter. When attacked by pathogenic factors, it often turns into cold syndrome, and it is not easy to get fever or low heat potential during the course of the disease, such as the symptoms of yin flourishing and yang declining. Therefore, foods or drugs that tonify yang have the function of keeping out the cold, especially after winter, eating such drugs or foods can improve the resistance of people with yang deficiency and cold.