Getting up in the morning with a dry mouth and bitter mouth may be caused by physiological factors, but also do not rule out periodontal abscess, gastroesophageal reflux disease and other pathological factors. 1. Physiological factors: If there is no water for a long time, and eat a lot of spicy, stimulating, greasy food before going to bed, it will lead to a lack of water in the body, so that the secretion of saliva is reduced, resulting in the second morning when you get up with a dry mouth, bitter and other uncomfortable symptoms. Secondly, sleeping at night in an environment with high temperature and low humidity may also lead to the above symptoms. This is a normal physiological phenomenon, usually after drinking more water will be improved. 2. Periodontal abscess: usually due to the aggravation of periodontitis, resulting in infection of the gum area, will lead to periodontal abscess, which will secrete a lot of pus. In the morning, there will be dry mouth, bitter mouth and other uncomfortable symptoms. You can follow the doctor’s advice to choose hydrogen peroxide solution, povidone-iodine, amoxicillin and other medications, if necessary, the flap surgery treatment. 3. Gastroesophageal Reflux Disease (GERD): It is usually due to the decrease of esophageal clearance and the decrease of esophageal mucosal resistance, which leads to the reflux of gastric acid and gastric contents into the esophagus, thus causing inflammatory lesions and reflux into the oral cavity. Therefore, after waking up in the morning, there will be dry mouth and bitter mouth and other uncomfortable symptoms. Omeprazole, domperidone and other medications can be chosen as prescribed by the doctor, and surgery can be performed if necessary. When the above symptoms occur, it is recommended to consult a doctor in a timely manner, under the guidance of the doctor to determine the cause of the treatment, the use of drugs need to comply with medical advice.