Mouth bitter sour, may be gums periodontal inflammation or tongue lesions, affecting the sense of taste, if the inflammation is obvious can be taken orally ornidazole and acetylspiramycin; gastric contents reflux into the oral cavity, can be taken orally cisapride and omeprazole and other gastric drugs to improve the symptoms. If it is caused by oral problems, you need to improve oral hygiene, dental caries, gingivitis, lingual inflammation, go to the hospital stomatology department to deal with dental or tongue problems; if it is caused by gastro-esophageal problems, you can use gastric stimulating drugs, antacids to improve symptoms. Oral hygiene problems, such as gums, periodontal inflammation, dental caries so that food residues remain fermentation, morning may appear bitter, sour mouth phenomenon, usually need to pay attention to improve oral hygiene, develop a good habit of brushing, after meals or before going to bed using mouthwash to improve the oral environment. If there is chronic gastritis, reflux esophagitis, gastric digestion function is poor, food in the stomach to stay in the fermentation or reflux into the esophagus and mouth, reflux mixed with gastric acid, can cause mouth acidity. Can be treated with gastric stimulants such as cisapride under the guidance of a doctor, as well as drugs such as omeprazole to make acid and colloidal bismuth pectin to protect the gastric mucosa.