Upstate gastroenterologist Sekou Rawlins, MD, tells about theories for the cause of inflammatory bowel diseases (or IBDs), including ulcerative colitis and Crohn's disease, but says it is not known for sure what causes these diseases. Some people are prone to developing an IBD, but it's likely that environmental factors such as where you live and what you eat, may play a role. He also talks about diagnosis and treatment of these diseases.