Ulcerative colitis is a chronic inflammation of the large intestine (colon). In patients with ulcerative colitis, ulcers and inflammation of the inner lining of the colon lead to symptoms of abdominal pain, diarrhoea and rectal bleeding. Ulcerative colitis is closely related to another condition of inflammation of the intestines called Crohn's disease. Together, they are referred to as Inflammatory bowel disease (IBD). Ulcerative colitis and Crohn's diseases are chronic conditions that can last for years.