Constipation and blood in stool may not necessarily be colon cancer, but may also be caused by chronic colitis or colon polyps or inflammatory bowel disease. Therefore, if a patient has constipation and blood in stool and wants to clarify whether it is colon cancer, he or she needs to undergo e-colonoscopy plus pathological examination before the final diagnosis can be made. For patients with constipation, if blood in stool occurs, it is mostly due to long-term constipation, which causes congestion, edema and erosion of the colonic mucosa, resulting in blood in stool, and the bleeding volume is relatively small. In addition, patients with hemorrhoids also often have constipation and blood in the stool. If long-term, repeated constipation can also cause anal fissure and lead to blood in the stool. Therefore, the final diagnosis needs to be confirmed by completing an e-colonoscopy plus pathological biopsy.