Most of the patients who suffer from senile dry mouth have disorders of the internal organs. Treating the primary disease while using TCM evidence-based treatment can effectively relieve the symptoms by treating both the symptoms and the root cause. Yin deficiency and fire type manifesting as thirst and excessive drinking, insomnia and dreaminess, dry stools, yellow urine, heat in the heart of the hands and feet, fine pulse, red tongue with yellow coating and dryness. The treatment is to nourish Yin and lower the fire, and Zhi Bai Di Huang Wan can be used to regulate. Spleen and Stomach Heat Patients are thirsty for more water and like cold drinks, yellow urine, dry stools, irritability, insomnia, red tongue with yellow coating and strong pulse. The treatment is to clear heat and lower fire, and Huang Lian Shang Qing Wan can be used to regulate. Weak spleen and stomach: dry mouth but does not want to drink water, or only drink a small amount of hot water, reduced food intake, poor digestion, light red tongue, slow and weak pulse, etc. The treatment is to warm the spleen and stomach, which can be treated with Tonic Zhong Yi Qi Pill. Kidney-Yin deficiency The patient shows dry mouth and prefers to drink water, but does not affect eating, urinates a lot, has soreness and weakness of the waist and knees, often accompanied by distraction and dizziness, red tongue with thin coating, atrophied tongue papillae, and fine pulse. The treatment is to nourish Yin and tonify the kidneys, which can be regulated with Liu Wei Di Huang Wan.