According to Crohn's and Colitis UK, there are many symptoms of IBD that people may not be aware of. Most know that stomach pains and blood in the stool are signs that something could be wrong, but did you know the following signs could also point to inflammatory bowel disease? Cankers (or mouth ulcers) Cankers can occur for many reasons, or for no reason at all. But those who struggle with IBD may regularly get mouth ulcers, particularly during flare ups. The cankers can vary in size and last up to 10 days. They are generally quite painful during the first few days. Learn more about ulcerative colitis from a patient’s point of view.