The appendix is a tiny tube attached to the large intestine that no longer has any real function. Appendicitis—inflammation and swelling of the appendix, usually as a result of bacterial infection—generally occurs between the ages of 10 and 19, and is the most common reason for emergency surgery in the U.S. today. Since the appendix has so little to do, appendectomies normally have no negative aftereffects at all. If appendicitis is ignored, bacteria may enter the blood and infect other parts of the body.