Whether bowel cancer is pain on the left or right side of the stomach depends on the location of the tumor. Generally, if the tumor appears in the left half of the colon, it usually shows pain in the left side of the abdomen, while if the tumor appears in the right half of the colon, it usually shows pain mainly in the right side of the abdomen. Because the large intestine is relatively long, it starts from the lower right abdomen, i.e., the ileocecal region, goes up to the lower part of the liver, then to the left to the lower part of the spleen, and finally goes down along the left abdominal wall to the pelvis and rectum. In general, tumors in the right hemicolectomy are usually characterized by anemia and cachexia, while tumors in the left hemicolectomy are usually characterized by intestinal obstruction. If patients experience changes in bowel habits and nature, black stools or bloody stools, they should actively go to the hospital for examination and treatment.