Bitter mouth when hungry may be related to reflux esophagitis, cholecystitis, chronic hepatitis and other causes. 1. Reflux esophagitis: If esophageal reflux occurs when you are hungry, gastric acid, bile and other digestive juices can enter your mouth and cause your mouth to become bitter. 2. Cholecystitis: If you suffer from cholecystitis, bile reflux can occur when you are hungry, resulting in a bitter mouth. 3. Chronic hepatitis: If you suffer from chronic hepatitis, the poor function of the gallbladder can lead to abnormal bile discharge, which can lead to bitter mouth when you are hungry. It is recommended to go to the hospital in time if the bitter mouth persists when you are hungry, so as to clarify the cause of the disease and standardize the treatment under the guidance of the doctor.