Sleeping at night to wake up at two or three o’clock in the morning dry mouth, common physiological factors, such as: incorrect sleep position, irregular diet, low water intake; also seen in pathological factors, certain diseases, such as: diabetes, dry syndrome, and so on. 1. Physiological factors: sleeping posture is not correct, open-mouth breathing, mental stress is too much, there will be two or three o’clock in the morning to wake up, eat too salty dinner, too sweet, drink less water, two or three o’clock to wake up will appear dry mouth. 2. Pathological factors: certain diseases, such as diabetes, blood sugar is too high, urination at night, the body’s water is reduced, waking up will appear dry mouth. Dry syndrome, can involve the salivary glands, mucous membrane secretion is reduced, causing dry mouth. Wake up at two or three o’clock in the morning after the dry mouth, you can drink more water, to the body to replenish water to relieve, such as not relieved, to the hospital in a timely manner, to find out the reasons for the cause of treatment.