Normally, having a colonoscopy cancer is not contagious. Bowel cancer, a tumor of epithelial origin of the intestinal tract, is not a contagious disease, and is not transmitted through the air, from mother to child, or through sexual contact, as is the case with contagious diseases such as pneumonia and AIDS. Bowel cancer can cause diarrhea, constipation, blood in the stool, changes in bowel habits and stool characteristics, and can be accompanied by symptoms such as anemia and weight loss. With the help of an electronic camera probe installed at the front end of the colonoscope, the colonoscopy will display the microscopic image on the monitor screen, so that the doctor can observe the intestinal mucosal lesions; during the examination process, it can also be directly carried out treatments, such as colonoscopic hemostasis, colonoscopic polypectomy, and so on. Colonoscopy should be cleaned and sterilized after each time it is done before it is used for the next patient, so theoretically it is impossible to transmit cancer by doing colonoscopy.