The digestive system is a set of organs (including the stomach, large and small intestines, rectum, and others) that convert the foods we eat into nutrients and absorb these nutrients into the bloodstream to fuel our bodies. We seldom notice its workings unless something goes wrong, as in the case of inflammatory bowel disease (IBD). It's estimated that up to 1 million Americans have inflammatory bowel disease. It occurs most frequently in people ages 15 to 30, but it can also affect younger children and older people. And there are significantly more reported cases in western Europe and North America than in other parts of the world. What Is Inflammatory Bowel Disease? Inflammatory bowel disease (which is not the same thing as irritable bowel syndrome, or IBS) refers to two chronic diseases that cause inflammation of the intestines: ulcerative colitis and Crohn's diseaseCrohn's disease. Although the diseases have some features in common, there are some impor