Traditional Chinese Medicine (TCM) believes that dry mouth and lumbar pain are mostly related to yin deficiency of the liver and kidneys (insufficient yin fluid in the liver and kidneys). Chinese medicine believes that the waist is the capital of the kidneys, and lumbago is mostly a manifestation of kidney deficiency. In addition, the foot syncopal liver meridian passes through the waist, so lumbar pain can also be caused by the liver meridian is not smooth. Insufficient yin fluid cannot be transmitted to the mouth and tongue, thus manifesting dry mouth and thirst. Therefore, dry mouth and lumbago are mostly related to Yin deficiency of the Liver and Kidneys. In the treatment, you can choose drugs that nourish the liver and kidney, such as Liu Wei Di Huang Wan. Liu Wei Di Huang Wan has the effect of nourishing yin and tonifying the kidney and can be used in the treatment of kidney yin deficiency, dizziness and tinnitus, lumbar and knee weakness (a feeling of soreness and weakness in the lumbar and knee areas), bone vapor and tidal fever (a burst of heat, feeling that the heat is penetrating from inside the bone to the outside), night sweating (abnormal sweating after falling asleep, but sweating stops when waking up), spermatorrhea, and dry mouth. This medicine should not be used with cold and flu medicines while taking it. Patients with dry mouth and back pain are advised to go to regular hospitals for consultation and treatment under the guidance of professional physicians who can identify the symptoms.