The causes of bitter mouth are commonly found in irregular diet, overeating, digestive system diseases, such as gastritis, cholecystitis, and mental factors, such as nervousness and stress. 1. Irregular diet, overeating, or eating too much stimulating food, which stimulates the gastrointestinal tract and causes bitter mouth symptoms. 2. Digestive system diseases, such as gastritis, Helicobacter pylori infection, etc. will appear bitter mouth, often accompanied by stomach discomfort; liver disease, cholecystitis patients will also appear bitter mouth symptoms. 3. such as mental stress, sleep quality is not good, stay up late, drink less water or eat less fruit caused by fire, by drinking more water, eat more fruits and vegetables bitter mouth will be better. There are many reasons for bitter mouth, if there is abdominal pain, stomach upset, we should go to the hospital in time for treatment.