Mouth is very bitter in the morning need to consider a variety of reasons, first of all, oral cavity drainage, to see if there are oral infections, such as oral ulcers, gingivitis, etc., to actively give brush teeth, rinse mouth, oral care, and the corresponding treatment. In addition, it is also necessary to make adjustments to diet and living habits, abstaining from greasy, fried, spicy and stimulating foods, and also quitting smoking and alcohol. If the symptoms of bitter mouth do not improve significantly, further liver and biliary ultrasound and gastroscopy are needed to evaluate whether there is a corresponding biliary tract disease or poor digestive function causing the symptoms of bitter mouth. Biliary tract diseases may cause bile reflux, which may lead to bitter mouth symptoms, while poor digestion may also cause bitter mouth symptoms, such as gastritis and gastric ulcer.