Bitterness in the mouth when patients wake up in the morning may be related to a variety of factors, commonly due to the following reasons: 1. Bile reflux: Patients can clarify whether there is bile reflux through gastroscopy, and also need to clarify whether it is caused by obstructed peristalsis of the gastrointestinal tract. For the above situation, patients should be given gastrointestinal motility drugs such as morpholine and loxacillin to promote gastrointestinal peristalsis and protect the gastric mucosa; 2, diabetes: diabetic patients can improve their symptoms by controlling blood sugar and maintaining normal blood sugar levels, which can effectively solve the problem of bitter mouth; 3, oral lesions: if the patient’s bitter mouth is caused by oral diseases such as mouth ulcers and gingivitis, the oral inflammation should be removed under the correct guidance and treatment of a dentist. If the patient’s bitter mouth is caused by oral diseases such as oral ulcer, gingivitis, etc., the patient needs to clear the oral inflammation under the correct guidance and treatment of the dentist to relieve the corresponding symptoms; 4. Immune system diseases: the patient’s bitter mouth may be caused by immune system diseases such as Leukocyte’s syndrome.