It is usually not possible to diagnose yin or yang deficiency solely on the basis of a single symptom of dry mouth and tongue, but dry mouth and tongue are common symptoms of yin deficiency, and it is recommended that the patient undergoes a face-to-face Chinese medicine examination to identify the symptoms. Yin deficiency may cause dryness due to insufficient Yin fluid in the body, including dry mouth and tongue, dry skin, dry stools, and may also be accompanied by five heart-heat (heat in the hearts of the hands and feet, and self-consciousness of the heart and chest), night sweating (abnormal sweating after going to sleep, and waking up and sweating stops) and other manifestations. Yang deficiency people, there are afraid of cold, cold limbs, cold sweat, tongue fat, drowsiness, like hot drinks, waist cool belly cool, urine clear long, eat cold food diarrhea and other symptoms. To summarize, dry mouth is a common symptom of yin deficiency, but you can’t diagnose yang or yin deficiency based on the symptoms of dry mouth alone, and it is recommended that patients seek medical attention to clarify the cause of the disease.