Bowel cancer does not necessarily cause abdominal pain, especially early stage bowel cancer has almost no clinical symptoms. Bowel cancer is a malignant tumor originated from the mucosal surface of the intestinal wall, which is equivalent to the inner side of the intestinal wall. When it first grows, it does not cause narrowing of the intestinal cavity and intestinal obstruction, so there is no abdominal pain, bloating, diarrhea and other uncomfortable symptoms at this time. Bowel cancer is divided into left and right colon cancer. The main symptoms of right colon cancer are emaciation, weakness, anemia and abdominal mass, and because the intestinal cavity is wider, it usually does not cause narrowing of the intestinal cavity and cause paroxysmal abdominal pain. On the other hand, the main symptoms of left colon cancer are abdominal pain, diarrhea, change in nature of stool, including mucus-purulent-blood stool, frequent stool, unclean stool, etc. In other words, left colon cancer is likely to cause abdominal pain due to intestinal stenosis and intestinal obstruction. In conclusion, early stage of bowel cancer will not cause abdominal pain, while left hemianopia is prone to abdominal pain, but whatever kind of bowel cancer will cause intestinal obstruction and abdominal pain in advanced stage, therefore, to prevent bowel cancer, regular colonoscopy 1-2 years is the best way.