There are many reasons that cause bitter mouth, there are generally the following situations: 1, poor oral hygiene, poor oral hygiene will cause gingivitis, periodontitis and other oral diseases, the symptoms of bitter mouth, patients can treat oral diseases, usually you can use fat sea, honeysuckle, chrysanthemum to drink water; 2, lack of trace elements, lack of zinc or vitamin B12 will lead to bitter mouth, vitamin B12 is needed through the intestinal tract to be digested and absorbed, lack of this vitamin, patients will have bitter mouth, nausea, loss of appetite and other symptoms; 3, indigestion. Clinically, patients with poor dietary habits and living habits, long-term exercise and exercise will lead to slower gastrointestinal peristalsis, food in the stomach for a long time will cause damp heat, patients will have symptoms of bitter mouth, it is recommended that patients actively exercise and exercise.