Winter is a cold season, and everything is cold. According to the theory of traditional Chinese medicine, cold corresponds to kidney, which is most likely to damage the yang of kidney. When the yang of the kidney is injured, it is prone to diseases such as cold pain in the waist and knees, fear of cold, frequent urination at night, impotence, nocturnal emission, etc. Deficiency of kidney yang and kidney yin can lead to dry throat, dizziness and tinnitus. Therefore, it is very important to pay attention to the maintenance of kidneys in winter. Kidney is the foundation of nature and the root of life. The strength of essence in kidney determines the growth and aging of people. Modern research believes that kidney qi is closely related to human immune function. Tonifying kidney in winter can not only enhance the cold resistance of human body, but also improve the immunity and disease resistance of human body and delay aging. The kidney governs the absorption of qi, and qi supplements the respiratory function of the lungs. Lung governs qi, and kidney is the root of qi. The kidney can absorb the clear air inhaled by the lungs and prevent the breathing from being superficial. If the kidney's inspiratory function is normal, the breathing will be even and harmonious. If the kidney does not inhale, there will be symptoms of wheezing, breathing more and inhaling less. Winter is the season of high incidence of respiratory diseases. Nourishing kidney is helpful for lung-qi breathing and preventing such diseases. The kidney dominates the bone and the tooth is the bone. Knocking teeth often in winter is good for both kidneys. Kidney produces marrow, its flowers are in the hair, and the brain is the marrow sea. Pay attention to strengthening the brain and strengthening the maintenance of hair in winter. The kidney is saliva in liquid, and the tongue reaches the palate in winter. Saliva can be swallowed slowly after it is full, which can nourish kidney essence. The meridians of the kidney start from the foot, and the spring of the heart of the foot is its main point. It is best to soak your feet with hot water before going to bed at night in winter and press the center of your feet. Kidney and bladder are exterior and interior, and essence in kidney contributes to transpiration and gasification of bladder urine. Tonifying the kidney in winter for the elderly can reduce urine and reduce frequent urination at night. The bladder meridian runs on the back, and the invasion of cold evil bears the brunt. Therefore, we should pay attention to keeping our backs warm in winter and wear cotton or wool vests to protect kidney yang.