Gallstones may cause bitterness in the mouth due to bile reflux. If gallstones are combined with severe cholecystitis, it will cause poor bile drainage and make it more likely that the symptoms of bitter mouth will occur. The pylorus and cardia of the stomach inhibit the reflux of bile so that food or stomach contents can be digested downward without reflux, which can occur when they become lax. In case of gallstones or combined cholecystitis, due to irregular bile excretion or infected bile discharge, the pylorus will be continuously stimulated, thus leading to the relaxation of the pylorus, and bile from the duodenum will flow back to the stomach and even reach the esophagus and mouth, thus causing the symptoms of bitter mouth. Mouth bitterness easily occurs in the morning when you wake up because you are lying flat during the night when you sleep, and when you wake up, bile is more likely to reflux and appear bitter due to the factor of gravity. In this case, patients should promptly control the inflammation of gallbladder by applying choleretic drugs, combining with diet control, exercise and avoiding eating before sleep, so as to reduce the probability of bile reflux and relieve the symptoms of bitter mouth. If the gallstones are severe, surgical treatment should be considered. In addition, it is important to further rule out whether there are other causes of bitter mouth, including mouth ulcers, gingivitis and laryngitis, which may cause bitter mouth. If gastrointestinal digestive malfunction, such as gastric ulcer, Helicobacter pylori infection, duodenal ulcer, or chronic diseases such as hypertension and diabetes, may also lead to the occurrence of bitter mouth, which needs to be combined with other clinical symptoms and examination to confirm diagnosis and active treatment.