Crohn's disease is a chronic nonspecific inflammatory disease, whose cause is currently unclear but may be related to immune mechanisms. Its main symptoms include abdominal pain, diarrhea, weight loss, and poor appetite. A colonoscopy can reveal longitudinal ulcers on the mucosa, distributed in segments. This disease has signs of lifelong recurrence, and currently, there are no specific effective medications, making treatment very challenging. The lesions can develop throughout the entire digestive tract. Chronic colitis primarily presents symptoms such as abdominal pain and diarrhea. A colonoscopy can show intestinal mucosal redness, swelling, and erosion. The condition generally responds well to treatment and is relatively milder compared to others.