Dry mouth and bitter mouth may be related to diet, oral diseases, gastrointestinal diseases and liver and gallbladder diseases. 1. Dietary factors: If you often eat spicy, cold and irritating food or have the habit of smoking and drinking for a long time, it is easy to trigger the symptoms of dry mouth and bitter mouth. 2. Oral diseases: if gingivitis, periodontitis or oral ulcers and other oral diseases, it is easy to induce the symptoms of dry mouth and bitter mouth, and even accompanied by a certain degree of pain. In the case of burning mouth syndrome, the patient will experience burning sensation in the mouth, dry mouth, and at the same time, there can be taste abnormalities, including bitter mouth. 3. Gastrointestinal diseases: If there are gastrointestinal diseases, such as gastric ulcer, duodenal ulcer or chronic gastritis, as well as intestinal dysfunction caused by constipation, it is easy to produce the symptoms of dry mouth and bitter mouth. 4. Liver and gallbladder diseases: when there are liver and gallbladder diseases, such as gallstones, cholecystitis, etc., easy to trigger the symptoms of dry mouth and bitter mouth, and bile secretion abnormalities have a direct relationship. If the symptoms persist for a long time or are accompanied by other abnormal manifestations, you need to consult a doctor as soon as possible to clarify the cause of the disease before treatment.