Left-sided abdominal distension and tenderness can be caused by alcohol consumption, consumption of high protein foods, constipation, intestinal infections and abdominal tumors. 1. Drinking a lot of alcohol and consuming a lot of high protein food can cause the intestinal lumen to produce more gas and accumulate in the intestinal tract, which can cause the symptoms of left abdominal distension and hidden pain. 2. Some patients with intestinal infections or constipation may also have left abdominal distension and pain. 3. For middle-aged and old patients who have left abdominal distension and hidden pain, they should pay attention to the possibility of tumors, such as left colon tumor, rectal cancer, etc., which can cause abdominal pain and abdominal distension. However, such patients often have abnormal defecation habit, change of stool character and other manifestations. Abdominal distension and bloating symptoms should be treated under physician’s guidance, and it is recommended to consult a doctor in time if there is any discomfort, and avoid taking medication on one’s own in order to avoid delaying the condition.