Diarrhea after drinking beer and alcohol stimulation of the gastrointestinal tract has a relationship, but also may be due to irritable bowel syndrome, colitis and other diseases. 1. Alcohol stimulation: beer contains alcohol, and alcohol into the body after the gastrointestinal mucosa will cause some irritation, gastrointestinal peristalsis accelerated, while the intestinal mucosal secretion of liquid increased, thus causing diarrhea after drinking beer phenomenon. There are also some patients who drink beer directly from the refrigerator. 2. Irritable bowel syndrome: the etiology is still unclear, but may be related to visceral hypersensitivity, abnormal gastrointestinal dynamics, intestinal microecological imbalance, etc., while food intolerance, medication, etc. are triggering factors. Therefore, some patients with irritable bowel syndrome caused by drinking beer after an acute attack may experience diarrhea, abdominal pain and other uncomfortable symptoms. 3. Colitis: some patients with colitis can also be manifested as diarrhea after drinking beer. Colitis is related to infection, immune factors, improper diet, etc. Typical symptoms of patients include diarrhea, abdominal pain, blood in the stool, and a sense of urgency and heaviness. It is recommended that people who have diarrhea after drinking beer should consult a doctor for examination to determine the cause of the disease and then take treatment measures as prescribed by the doctor.