Crohn's disease and ulcerative colitis are considered invisible illnesses, in that you are unlikely to know that someone is suffering from either disease just by looking at them. Telling a Crohn's or colitis patient that they don't look ill isn't very helpful to a person who is trying to hold it all together. If someone tells you that they have an inflammatory bowel disease you may feel the urge to make a comment that you think is OK, when actually it could be quite hurtful to the person suffering. Here are seven other things you shouldn't say to a person with Crohn's disease or ulcerative colitis according to CBS News: While irritable bowel syndrome can be uncomfortable, it isn't the same as inflammatory bowel disease and it's unfair to compare the two. You may feel like you're sympathizing, but you're actually dumbing down their condition. Find out about professional strongman, Clint Darden's, battle with ulcerative colitis.