The more you drink, the drier your mouth becomes. This may be related to diabetes, dry syndrome, uremia, vitamin deficiency, and nervous thirst. 1. Diabetes: diabetes will appear dry mouth, drinking and urinating, and other manifestations, with elevated blood glucose, blood osmotic pressure increases, resulting in the more you drink water, the more dry mouth. 2. Dry syndrome: the body’s hormone metabolism disorders, dry mouth, dry eyes, fatigue and other symptoms, resulting in the more you drink water, the more dry mouth. 3. Uremia: lack of antidiuretic hormone, or the kidneys are not sensitive to it, resulting in impaired reabsorption capacity of the renal tubules, large amounts of urination, extreme thirst, irritability and other symptoms, resulting in the more you drink the more dry your mouth becomes. 4. Lack of vitamins: vitamin deficiency affects cellular antioxidant response, resulting in the mucous membrane can not be normally renewed, affecting the formation of epithelial cells, appearing oral mucous membrane dryness, resulting in the more you drink water, the drier your mouth. 5. Neurological thirst: long-term habitual drinking of large amounts of water, inhibit the body’s antidiuretic hormone, resulting in a mental feeling of thirst, repeated drinking, frequent urination, fatigue and other symptoms, but also the more you drink water the more dry mouth. The more you drink, the drier your mouth, it is recommended to go to the hospital in time for examination, to clarify the cause of the disease, active treatment, to avoid affecting your health.