Ulcers on the rectum are not necessarily cancer, but need to be analyzed according to the morphology of the ulcers, the depth of infiltration and other comprehensive conditions to determine whether they are cancer. 1. Ulcers on rectum are usually the clinical manifestation of proctitis. If the shape of ulcers is complete, the boundary is clear and the infiltration depth is shallow, it can be considered as benign disease such as proctitis. Patients may experience symptoms such as vomiting, abdominal pain or diarrhea, which can be treated with immunosuppressive drugs, and it is recommended to take the appropriate medication under the guidance of a doctor. 2. Ulcers on the rectum may also be a sign of cancer. If the ulcers are irregular in shape, with unclear boundary or dirty white moss on the surface, there is a higher probability that they are cancerous. It is recommended that patients go to the hospital as soon as possible to improve the pathological biopsy of the ulcers, so as to have a comprehensive analysis of the further diagnostic and therapeutic plan given by the professional doctor.