Colon ulcer is not cancer. Colon ulcer is a chronic inflammatory bowel disease, while colon cancer is a malignant tumor. Colon ulcer can be clinically manifested as diarrhea, abdominal pain, mucopurulent stool, and some patients can have fever, weakness, and emaciation, while colon cancer can also show the above symptoms. Many patients with colon cancer can show clinical manifestations of intestinal obstruction, but colon ulcer rarely shows the above-mentioned manifestations. The manifestation of colonoscopy is also different between the two, and the diagnosis of colon cancer or colon ulcer can be confirmed after histopathological specimen examination. For colon ulcers, anti-inflammatory treatment is generally used, and the disease can be effectively relieved after treating the cause. Colon cancer can only be effectively controlled through surgery, radiotherapy and chemotherapy, and colon ulcers may have cancerous tendency if they are not cured for a long time, which needs to be paid attention to clinically.