The main purpose of biopsy in patients with terminal ileal ulcers is to characterize the lesion and to avoid missing the diagnosis of malignant lesions. Terminal ileal ulcers are pathologic ulcerative changes in the terminal region of the ileum. Common causes include acute and chronic enteritis, Crohn’s disease, ulcerative colitis, mesenchymal tumors, intestinal polyps, and malignant tumors. Any ulcerative changes found at the end of the ileum during colonoscopy should be biopsied. A portion of the diseased tissue is obtained and the final lesion is diagnosed by biopsy. Organic disease of the ileum rarely occurs and can usually be diagnosed by symptoms, physical examination, laboratory tests, and ancillary tests, and treated accordingly. If an ulcer is found in the ileum by colonoscopy or small bowel examination, a biopsy can be taken to further clarify the diagnosis and appropriate treatment can be given.