Kidney Yin, as the source of Yin energy in the body, nourishes and moistens various organs and tissues, nourishes the brain and marrow, bones, and restrains excessive Yang. Kidney Yin deficiency syndrome refers to the syndrome manifested by the deficiency of Kidney Yin, leading to loss of nourishment and the generation of internal heat. As one of the common basic patterns in clinical practice, it is mainly caused by chronic illness damaging the kidneys, inadequate innate endowment, excessive sexual activity, and the overuse of warm and dry Yin-depleting substances. The main symptoms include lumbago and knee pain, dizziness and tinnitus, loose or painful teeth, premature ejaculation in men, scanty or absent menstruation in women, insomnia, forgetfulness, dry mouth and throat, and even irritability, restlessness, night sweats, afternoon flushing, emaciation, constipation, scanty urine, red tongue with little saliva, less or no coating, and thin and rapid pulse. It is widely seen in traditional Chinese medicine for conditions such as low back pain, edema, polydipsia, nocturnal emission, tinnitus, hearing loss, headache, dizziness, and asthenia. It is also commonly seen in modern medicine for conditions such as diabetes, acute and chronic nephritis, hypertension, tuberculosis, osteoporosis, and hyperthyroidism.
Liuwei Dihuang Wan is a representative formula in traditional Chinese medicine for nourishing Yin and tonifying the kidneys. Liuwei Dihuang Wan was developed by the famous Song dynasty physician Qian Yi and first appeared in his book "Xiao Er Yao Zheng Zhi Jue". It consists of six herbal ingredients: prepared Rehmannia root, dogwood fruit, Chinese yam, water plantain, tree peony bark, and Poria. The formula contains the six tastes of sour, bitter, sweet, spicy, salty, and bland.
In Liuwei Dihuang Wan, prepared Rehmannia root is the emperor herb, and dogwood fruit and Chinese yam are the minister herbs. These three herbs work together to nourish the liver, spleen, and kidneys, with a focus on supplementing Kidney Yin and treating the root cause. Water plantain, tree peony bark, and Poria are the assistant herbs, which help to eliminate dampness and turbidity, balance excessive conditions, and treat the symptoms. Among them, prepared Rehmannia root nourishes the kidneys and fills the essence, dogwood fruit nourishes the liver and kidneys and astringes the essence, Chinese yam supplements the spleen and kidneys and consolidates the essence, and Poria seeps and dispels dampness in the spleen, assisting Chinese yam in supplementing the spleen. Water plantain clears and drains Kidney Fire, preventing the greasiness of prepared Rehmannia root, and tree peony bark clears and drains Liver Fire, counteracting the dampness of dogwood fruit. "Sour, bitter, sweet, spicy, salty, bland, the six tastes are named after them, and the name Dihuang emphasizes its strong tonifying effect on the kidneys." Liuwei Dihuang Wan treats both the root cause and the symptoms, making it the first choice for Yin deficiency in women.
Experts suggest that Dihuang Wan is composed of pure Yin-nourishing substances, and it should be avoided by those with Spleen deficiency, weak Qi, and digestive problems. While taking Yin-nourishing herbal medicines, it is advisable to consume more fresh vegetables, fruits, foods high in fiber and vitamins, and foods rich in high-quality protein. Spicy and stimulating foods should be avoided, as well as warm, dry, fried, and oily foods that can cause internal heat.
