The mouth is very dry has been drinking water is useless, may be dry syndrome, diabetes, salivary gland stones and other factors, need to correspond to the treatment. 1. Dry syndrome: dry mouth is one of its main manifestations, the patient’s salivary secretion is reduced, swallowing difficulties, may also appear caries, need to go to the hospital for examination and corresponding treatment. 2. Diabetes: mainly because the patient is in the situation of high blood sugar for a long time, there may be symptoms of dehydration, resulting in the manifestation of dry mouth, you can use dulaglucagon, metformin and other drugs to treat. 3. Salivary gland stones: Due to the high bacterial content in the mouth, causing symptoms such as salivary gland stones, dry mouth occurs, and can be treated with surgery to remove the stones or conservative treatment. Patients with long-term symptoms have not been improved, should go to the hospital for treatment, so as not to delay the condition, resulting in adverse consequences, the use of drugs need to follow the doctor’s instructions.