It is not possible to generalize which department to consult for bitter mouth and bad breath, and it is necessary to combine the accompanying symptoms and medical history to choose the appropriate department, such as stomatology, gastroenterology, liver and gallbladder surgery, and so on. If the patient has bleeding gums when brushing teeth or biting hard objects, and the color, shape and texture of the gums change, accompanied by bitter mouth and bad breath, it is considered to be caused by gingivitis, and need to go to the stomatology department. If the patient has bitter mouth and bad breath, accompanied by bloating, belching, anorexia, acid reflux and other discomforts, it is considered to be caused by Helicobacter pylori infection, and needs to go to the Gastroenterology Department for consultation. If the patient has a history of biliary colic, symptoms such as anorexia of fatty foods, belching, and vague pain in the right upper abdomen, accompanied by bitter mouth and bad breath, it is considered to be caused by chronic cholecystitis, and needs to go to the Department of Hepatobiliary Surgery. If you are unsure of which department to visit, ask at the hospital’s medical desk and seek help from the medical staff.