Ulcerative colitis is a chronic inflammatory bowel disease that primarily affects the colon and rectum, leading to inflammation, ulcers, and gastrointestinal symptoms such as diarrhea and abdominal pain. The condition is believed to result from an abnormal immune response and can range from mild to severe. Treatment often involves medication to reduce inflammation and manage symptoms, and in some cases, surgery may be necessary. It is a significant focus of medical research due to its impact on quality of life and healthcare costs.