The appendix is a small hollow tube attached to the cecum in the gastrointestinal system. While its exact function is unclear, it is thought to support the immune system by housing beneficial gut bacteria and exposing white blood cells to antigens. Appendicitis, a painful inflammation of the appendix, can occur if the opening becomes blocked by hardened stool or other obstructions. The standard treatment for appendicitis is an appendectomy, a minor surgery to remove the appendix.