A long and loud fart refers to defecation, which may be caused by food stimulation, indigestion, mental stimulation, intestinal inflammation and other conditions. 1. Food irritation: If the patient has recently eaten some foods that are more likely to produce gas, it will cause the food to be broken down in the intestines, resulting in excessive gas and long, loud farts during defecation. Such foods include sweet potatoes, onions and soybeans. 2. Indigestion: If the patient himself has indigestion, there will be abdominal pain and loud fart. 3. Mental stimulation: If the patient is too nervous or anxious, it may lead to irritable bowel syndrome and intestinal reactions. 4. Enteritis: If the patient has enteritis, there will be bacterial growth to form more gas discharge, may also be accompanied by obvious diarrhea and other symptoms. It is recommended that the patient should consult a doctor in time to do a systematic examination, to clarify the causes of such symptoms, and actively treat them.