The most common reason for bitter mouth after meals is that bile refluxes into the stomach, causing damage to the gastric mucosal membrane and causing bitterness in the mouth. Second, combined with biliary tract diseases, especially cholecystitis and gallbladder stones cause gastrointestinal dysfunction, and bile cannot enter the jejunum normally after eating, resulting in bitterness in the stomach. Third, other related diseases, including hepatitis, tumors, ascites, cirrhosis and other diseases, cause dysfunction of the entire gastrointestinal tract and eventually lead to poor digestive function, allowing bile to reflux into the stomach through the duodenum. In short, the root cause of bitterness in the mouth after meals is the reflux of bile into the stomach due to some kind of original, causing the symptom of bitterness in the mouth.