Usually there is no diarrhea after drinking coffee, but there are several reasons for diarrhea after drinking coffee: 1, whether there is a problem with the quality of coffee, causing acute gastroenteritis and diarrhea. 2, such as the existence of chronic gastritis or ulcerative colitis patients, after taking coffee to stimulate the secretion of large amounts of gastric acid, promote gastrointestinal peristalsis and lead to the patient to appear secretory diarrhea, which will appear violent diarrhea accompanied by abdominal pain and other clinical symptoms. 3, such as patients suffering from ulcer disease, such as gastric ulcer, duodenal ulcer, etc., easily under the action of caffeine to produce excessive secretion of gastric acid, which will cause the typical symptoms of indigestion, accompanied by acid reflux, heartburn, diarrhea is obvious, the formation of watery stools, etc., should not continue to drink coffee.