It is possible to detect bowel cancer when checking blood, patients can check tumor marker or blood routine, if tumor marker is obviously elevated, for example, CEA is elevated, it suggests that patients may have bowel tumor. At the same time, if the routine blood test reveals that the red blood cells and hemoglobin have decreased, that is, the patient has anemia, which indicates that there is a possibility of intestinal tumor, and it is suggested to check colonoscopy or abdominal and pelvic CT test at the same time. If colonoscopy can find a mass inside the intestinal cavity, or CT examination finds that there is an occupation and a mass in the intestinal tract, it can generally suggest that it is intestinal cancer, and the pathology can be taken at the time of colonoscopy, which can further clarify the diagnosis.