Winter is the season when everything in nature closes. The basic principle of keeping in good health in winter is to conform to storing yang in the body, and to gather yin and protect yang as the foundation. Because the yang is hidden and the metabolism level of human body is relatively low, it is necessary to rely on the "kidney" as the motive force of life to ensure that life activities adapt to natural changes. According to the theory of traditional Chinese medicine, the kidney is "the origin of nature" and "the source of life". Its physiological functions are storing essence, controlling water, controlling qi, controlling bone and generating marrow, which are closely related to human bones, blood, skin, teeth and ears. Huangdi Neijing pointed out: "If you go against the winter season, the yin will not be hidden and the kidney will sink alone." Shaoyin here refers to the kidney. Different from western medicine, the kidney of traditional Chinese medicine refers to the whole functional system of the kidney. Kidney governs storing essence, which is the foundation of yin and yang of human body. The main bone produces marrow, which should flourish in winter. Traditional Chinese medicine believes that the energy and heat of human body come from kidney, which has strong function and vitality, but weak function and vitality. In winter, if the kidney can maintain normal physiological function, it can adapt to the climate change in severe winter and maintain normal metabolism.