Diarrhea once eating greasy food may be caused by chronic gastroenteritis, dyspepsia, irritable bowel syndrome, cholecystitis and so on. 1. Chronic gastroenteritis: it usually has symptoms such as bloating and abdominal pain, and if you eat greasy food, it will easily stimulate the stomach and intestines, leading to diarrhea. 2. Indigestion: if the patient consumes too much greasy food, it is not easy to be digested, and it will also stimulate the intestinal peristalsis too fast, leading to diarrhea. 3. Irritable Bowel Syndrome (IBS): patients with persistent or intermittent episodes of abdominal pain, abdominal distension, change in bowel habits and stool characteristics as the clinical manifestations, patients may experience diarrhea after eating greasy food. 4. Cholecystitis: acute episodes of epigastric pain, gradually developed to paroxysmal colic, satiety, eating fatty foods often trigger attacks, while the symptoms of diarrhea. As soon as you eat greasy food on diarrhea, it is recommended to consult a doctor in time to identify the cause of targeted treatment. Patients should eat a light and easily digestible diet, do not eat too greasy food.