Ulcerative colitis biopsy has the role of auxiliary diagnosis and exclusion of cancer. 1. Auxiliary diagnosis: biopsy is one of the diagnostic criteria for ulcerative colitis and is an important indicator for confirming the diagnosis of ulcer. 2. Ulcerative colitis has the risk of cancer and requires regular follow-up colonoscopy and biopsy as appropriate according to the microscopic manifestations. Ulcerative colitis may cause abnormal proliferation of intestinal mucosa to form colonic polyps, which is likely to be a precancerous lesion. With the growth of polyps, or after recurrent episodes of ulcerative colitis, it may lead to cancerous invasion of polyps into the surrounding tissues and blood vessels, which will lead to symptoms such as bleeding in stools, abdominal pain, etc. Biopsy can remove the localized lesions, which can be used for the diagnosis of ulcerative colitis, and can also be used for the diagnosis of cancer. Biopsy can remove the localized diseased tissue and send it to the laboratory for pathological biopsy to find out whether the diseased area or polyp is cancerous or not, so as to understand the extent of cancer at an early stage, and to formulate a treatment plan based on the biopsy results. Patients with ulcerative colitis are advised to consult a doctor in time for targeted treatment. Please do not take medication on your own to avoid delaying your condition.