Bitter mouth is considered to be oral diseases, gastrointestinal diseases, liver and gallbladder diseases, etc., according to the cause of the medication prescribed by the doctor. 1. Oral disease: gingivitis, dental caries patients, saliva secretion can not rinse the oral cavity bacteria or necrotic shedding cells, can appear bitter mouth. Can follow the doctor’s instructions to use antibacterial mouthwash gargle, such as 0.12% ~ 0.2% chlorhexidine, while receiving cleaning or filling treatment. 2. Gastrointestinal diseases: such as chronic gastritis, patients with poor gastric dynamics, resulting in bile reflux, bitter mouth. Patients can take bismuth quadruple regimen as prescribed for proton pump inhibitors (PPI) such as pantoprazole, esomeprazole + bismuth such as bismuth potassium citrate, bismuth pectin, etc. + 2 antimicrobial drugs such as amoxicillin, metronidazole. Acid-suppressing drugs H2 receptor antagonists such as cimetidine, ranitidine for treatment. 3. Hepatobiliary diseases: such as cholecystitis, inflammation of the liver and gallbladder lead to poor gallbladder function, bile excretion is not normal, there will be bitter mouth. Patients can follow the doctor’s instructions to take anti-infective aminobenzylpenicillin, clindamycin, choleretic drugs such as 50% magnesium sulfate, ursodeoxycholic acid tablets. If the symptoms of bitter mouth are more serious, it is recommended to consult a doctor to find out the specific cause. Common causes of bitter mouth include poor oral hygiene, indigestion, etc., which need to be treated according to the cause.