Bad stomach diarrhea may be caused by irritable bowel syndrome, atrophic gastritis, gastrinoma and other diseases. 1. Irritable bowel syndrome: studies have shown that the occurrence of this disease is related to gastric hypersensitivity, abnormal gastrointestinal dynamics, intestinal microecological imbalance, intestinal infections and other reasons. Typical symptoms include abdominal pain, abnormal defecation, etc. In some cases, persistent or intermittent diarrhea will occur, so the bad stomach and diarrhea may be caused by irritable bowel syndrome. 2. Atrophic gastritis: the main cause of this disease is caused by Helicobacter pylori infection, but also related to gastric mucosal damage factor, duodenal reflux and other reasons. It can be induced by anxiety, depression, exertion and other factors. Generally, patients with serious conditions will have symptoms such as diarrhea, tongue inflammation, emaciation and anemia. 3. Gastrinoma: the etiology of this disease is not clear, may be related to pancreatic α1 cell gene mutation, because the tumor will secrete a lot of gastrin, causing stimulation to the wall cells, so that its proliferation and secretion of a large amount of gastric acid and gastric juices, so that the patient will have diarrhea, abdominal pain and a series of symptoms. It is recommended that patients with bad stomach and diarrhea should go to the hospital for consultation, and cooperate with the doctor for active treatment after clarifying the specific cause.