What Is an Appendix, and What Does It Do? Everyday Health Menu NewslettersSearch Appendicitis What Is the Appendix and What Does It Do The role of the appendix has long been something of a mystery, but experts now believe they’ve learned much more about its function. By Joseph Bennington-CastroMedically Reviewed by Kacy Church, MD Reviewed: September 22, 2022 Medically Reviewed Your appendix is located in the lower right section of your abdomen. The appendix is a thin, roughly four-inch-long tube that’s part of your gastrointestinal (GI) tract. ( Where in Your Body Is Your Appendix Located Your appendix is located in the lower right part of your abdomen, in an area that doctors refer to as McBurney’s point. If applying pressure on McBurney’s point results in pain or tenderness, your doctor may suspect that you have More on the GI Tract 11 Tips for Better Digestive Health The muscles lining your GI tract, along with the hormones and enzymes that the system produces, allow your GI tract to break down and process food. Your appendix doesn’t directly help with digestion. It’s been unclear what role the appendix has in the body, and removal of the organ doesn’t appear to have any negative health consequences. For many years, scientists believed the appendix was a vestigial organ — one that lost its original function through centuries of evolution. Researchers thought that no other mammals had an appendix, aside from our closest ape relatives. What’s more, the cecum (a part of the large intestine) of plant-eating mammals is far larger than it is in humans. On this basis, Charles Darwin theorized that our distant ancestors also had large ceca, which allowed them to dine on leaves like the herbivores of today.But as these ancestors shifted to a diet based on fruits, which are easier to digest, their ceca shrank. The appendix, Darwin believed, is just a shriveled up part of the cecum, which evolution hasn’t entirely eliminated. ( The Safe House Theory of the Appendix br class lsbr Some scientists now believe the appendix is not useless after all, and may help our guts recover after a More on Digestive Health 9 Common Digestive Conditions From Top to Bottom The appendix contains a particular type of tissue associated with the lymphatic system, which carries the white blood cells needed to fight infections. In recent years, scientists have found that lymphatic tissue encourages the growth of some beneficial gut bacteria, which play an important role in human digestion and immunity.Studies have also shown that the lining of the gut contains a biofilm, or a thin layer of microbes, According to the so-called “safe house” theory, the appendix protects a collection of beneficial gut bacteria when certain diseases wipe them out from elsewhere in the GI tract. Once the immune system has rid the body of the infection, the bacteria emerge from the appendix biofilm and recolonize the gut. ( A review of the relevant available research published in 2016 concluded that the appendix is not a rudimentary organ but an “important part” of the immune system. ( Researchers have recently found that numerous animals, including great apes, other primates, opossums, wombats, rabbits, and certain rodents all have structures similar to the appendix. ( Potential Health Issues Involving the Appendix Sometimes, the appendix can become inflamed and infected, resulting in a condition called appendicitis. Appendicitis is often the result of an abdominal infection that has spread to the tiny organ, or some kind of obstruction that has blocked the small opening of the appendix. Sources of blockage include, among other things:Hard pieces of Additional reporting by Deborah Shapiro. NEWSLETTERS Sign up for our Digestive Health Newsletter SubscribeBy subscribing you agree to the Terms of Use and Privacy Policy. Editorial Sources and Fact-Checking Appendix Anatomy. Show Less The Latest in Appendicitis Symptoms of Appendicitis: Nausea, Fever, Abdominal Pain, and MoreBy Joseph Bennington-CastroSeptember 22, 2022 Appendicitis Causes, Complications, and Risk Factors If not treated, the appendix can burst and cause a potentially life-threatening illness.By Joseph Bennington-CastroSeptember 4, 2022 What Is a Ruptured Appendix? Causes, Treatment, and ComplicationsBy Joseph Bennington-CastroAugust 22, 2022 What Is Appendicitis? Symptoms, Causes, Diagnosis, Treatment, and PreventionBy Joseph Bennington-CastroAugust 20, 2020 Treating Appendicitis With AntibioticsBy Joseph Bennington-CastroMay 31, 2018 Appendicitis in Children: Signs, Symptoms, and More The signs and symptoms of appendicitis, as well as the treatment, can be different in children than in adults.By Joseph Bennington-CastroMay 31, 2018 What Is an Appendectomy? Surgery and Recovery An appendectomy is a surgical procedure to remove your appendix, the small tube connected to your large intestine in the lower right side of your belly...By Joseph Bennington-CastroMay 31, 2018 Abdominal Pain: Is It Appendicitis or Something Else? Several conditions can cause pain in the lower right abdomen, and can be difficult to distinguish from the symptoms of appendicitis pain.By Joseph Bennington-CastroMay 31, 2018 Chronic Appendicitis: Less-Severe but Nearly Continuous Abdominal Pain Sometimes the symptoms of appendicitis come and go and aren’t immediately apparent. What causes appendix pain to return?By Joseph Bennington-CastroMay 30, 2018 Study Shows Depression Affects IBD Patients and Their Siblings New research is the first to show a bidirectional link between inflammatory bowel disease and depression.By Ashley WelchOctober 6, 2022 MORE IN What Is a Ruptured Appendix? 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