Traditional Chinese Medicine (TCM) believes that soreness and weakness in the lower back and knees are caused by kidney deficiency. Depending on the specific clinical symptoms, it can be classified as either kidney yin deficiency or kidney yang deficiency. The treatment methods vary based on the diagnosis. Kidney yin deficiency primarily manifests as low-grade fever, restlessness, flushed face, dry mouth, dizziness, tinnitus, and soreness and weakness in the lower back and knees. The treatment focuses on nourishing kidney yin, often using modified formulations such as Liuwei Dihuang Tang (Six-Ingredient Rehmannia Decoction) or Zuogui Yin (Left-Restoring Drink). Key herbal ingredients include Rehmannia (Shu Di), Cornus (Shan Zhu Yu), Moutan Bark (Dan Pi), Lycium Fruit (Gou Qi), Ligustrum (Nü Zhen Zi), and Chinese Yam (Shan Yao). Rehmannia, Cornus, Lycium Fruit, and Ligustrum work to nourish kidney yin, while Chinese Yam strengthens both the spleen and kidneys, and Moutan Bark clears heat and cools the blood.

