If you have bitter mouth every time you wake up, you need to check the liver and biliary ultrasound and gastroscopy to see if there is any nocturnal bile reflux. If there is a biliary tract disease at night, the bile is discharged irregularly and the pylorus and cardia are relaxed, which will easily lead to the reflux of bile from the duodenum into the stomach and then into the esophagus and reach the mouth, thus causing the symptom of bitter mouth when waking up. In addition, it is also necessary to exclude whether there are diseases of the mouth itself, as well as bad eating habits and living habits, such as infections in the mouth, smoking, alcohol consumption, poor digestion, long-term eating of greasy and fried food, and gastrointestinal dysfunction. Therefore, further detailed examination is needed to clarify whether the symptoms of bitterness in the mouth can be relieved by first improving the living habits, personal habits and eating habits.