NHS information about ulcerative colitis, a long-term condition that affects your large bowel (colon). Read about symptoms, flare-ups, how it's treated and things you can do yourself to help. Ulcerative colitis (UC) is one of the two types of inflammatory bowel disease (IBD), with the other type being Crohn's disease. [1] It is a long-term condition that results in inflammation and ulcers of the colon and rectum. [1][7] The primary symptoms of active disease are abdominal pain and diarrhea mixed with blood (hematochezia). [1] Ulcerative colitis (UC) is the most common type of inflammatory bowel disease (IBD). It affects the inner lining of the colon and rectum, causing complete damage to the lining. People with UC often experience blood or mucous in their stool (poop) and feel an urgent need to empty their bowels. What is ulcerative colitis? Ulcerative colitis is an inflammatory disease that usually begins in the rectum, then worsens to involve some or all of the large intestine. Ulcerative colitis is a lifelong condition. Ulcerative colitis may begin with a breakdown in the lining of the intestine. Ulcerative colitis (UC) is a lifelong condition that causes inflammation and ulcers inside your colon (large intestine). UC is one of the most common types of inflammatory bowel disease (IBD), alongside Crohn’s disease. Learn more about the diagnosis and treatment of Ulcerative colitis. Find tips to get ready for any appointments you need. Ulcerative colitis (UC) is an inflammatory bowel disease. It causes irritation, inflammation, and ulcers in the lining of your large intestine (also called your colon). What is ulcerative colitis? Ulcerative colitis (UC) is a condition that causes inflammation and ulcers in the colon, which includes the large intestine and rectum. It’s a type of inflammatory bowel disease (IBD). UC can be mild in some people, while others have more severe symptoms. Ulcerative colitis is an inflammatory bowel disease that causes chronic inflammation and ulcers in the superficial lining of the large intestine, also called the colon. Read about ulcerative colitis symptoms, including early warning signs, intestinal and extraintestinal effects, and when to seek medical help.