In very extreme cases, ulcerative colitis affects the large intestine as a whole. Symptoms of ulcerative colitis include: diarrhea (when severe diarrhea is present, the person can have diarrhea from 10 to 20 times a day), rectal bleeding, and some people can confuse cramps for stomach or abdominal pain, weight loss, and fever. Most people who suffer from ulcerative colitis become diagnosed before the age of 30. The most commonly performed tests done in order to diagnose ulcerative colitis include: a biopsy, a colonoscopy, a stool sample, and venous blood tests. Once people have ulcerative colitis for 8 years or more, chances are that it might later become colon cancer. Ulcerative Colitis (2005-2015) WebMD Retrieved from