Bitter mouth may be caused by oral diseases, reflux esophagitis, liver and gallbladder diseases. 1. Oral diseases: such as dental caries, can lead to a large number of food residues left in the cavity, in the bacterial decomposition of the role of corruption and odor, the symptoms of bitter mouth. 2. Reflux esophagitis: the stomach contents of patients with reflux esophagitis are often mixed with bile, and when the disease strikes, not only will there be acid reflux, heartburn, but also the phenomenon of bitter mouth. 3. Hepatobiliary diseases: such as cholestasis, bile reflux, etc., due to the patient’s bile excretion abnormalities, can also appear bitter mouth phenomenon. It is recommended that people with a bitter mouth should seek medical attention in a timely manner to clarify the cause of the disease and standardize the treatment under the guidance of the doctor.