The Appendix is a tube like sac that averages 9 cm in length and is connected to the large intestine right about where it joins the small intestine. It has long been thought that the appendix is a so-called vestigial organ that serves no modern function.
That turns out to be incorrect. While the appendix is not useful for digestion, it is important to gut health and battling infection. It turns out that many types of “good” gut bacteria live in the appendix and those gut bacteria migrate to the rest of the digestive system when other good gut bacteria have been flushed from the intestines due to infection. During a digestive track infection, the intestines are cleared of fluid, nutrients and good bacteria (mainly via diarrhea). Because the appendix is shaped the way it is and due to it’s location, it is able to shield good bacteria from the infection and those bacteria repopulate the intestines with beneficial gut flora.
In addition to housing gut bacteria, the appendix also is home to a particular type of immune system cells called innate lymphoid cells which help protect the body from infection.
As a result of these discoveries over the past few years, doctors are less inclined to recommend the removal of the appendix in the cases of minor appendicitis and will lead to fewer unnecessary appendectomies. There are some non-surgical treatments for appendicitis that might be tried before removal is recommended.