Bitter mouth after eating greasy food is considered to be a symptom caused by indigestion and bile reflux. Greasy food is not easy to digest when it enters the gastrointestinal tract, which can easily lead to indigestion, especially if you suffer from gastric diseases, such as chronic gastritis, gastric ulcer, etc., which can lead to decreased digestive function, and after eating greasy food, you will experience symptoms such as loss of appetite, bloating and other discomforts, which can also lead to the manifestation of a bitter taste in the mouth. There is also the possibility that the phenomenon is caused by bile reflux, such as bile reflux gastritis, due to bile reflux from the duodenum to the stomach, which causes the symptoms. Eat oil things bitter mouth patients should try to light and easy to digest food, avoid eating greasy food, if necessary, need to go to the hospital, cooperate with the doctor treatment.