Stomach disorders may cause bad breath and bitterness. Common stomach disorders, such as chronic gastritis, gastric ulcers, peptic ulcers, stomach tumors, and other diseases, usually cause indigestion, abdominal bloating, and other symptoms, as well as bitter mouth and bad breath. Patients with gastric disease will experience bitter mouth due to indigestion, accumulation of more food in the body and reflux of stomach acid into the esophagus, which can cause reflux esophagitis or bile reflux gastritis. Gastric patients with poor peristaltic function of the intestines and stomach, there will also be a buildup of food is not easy to digest, too much food will be fermented in the patient’s body, which will produce more unpleasant, uncomfortable gas, and then appear in the case of bad breath. In daily life, not brushing teeth or consuming certain foods (e.g. stinky tofu, durian, bitter coffee, etc.) can also lead to transient bad breath and bitterness. In addition, certain diseases such as diabetes mellitus and purulent bronchitis can also lead to cases of bad breath. When stomach discomfort occurs, you should seek medical attention, consult a professional doctor, and under the doctor’s guidance, carry out scientific and effective treatment.