What Does the Appendix Do?

The appendix is a small organ located in your lower right abdomen. Although the medical community has been aware of the appendix for centuries, the function of this organ is not clear or fully understood.

This article will explain more about the appendix and how to recognize signs of appendicitis (inflammation of the appendix).

Person feeling appendix pain

Shidlovski / Getty Images

Where Is Your Appendix?

The appendix is a small tube that is located in the lower right side of your abdomen. The appendix branches off from the large intestine. It resembles a finger or worm.

What Does the Appendix Do?

The appendix was discovered 400 years ago, but its function was not clear. Charles Darwin believed the appendix was a useless leftover organ from evolution that served no purpose.

For centuries, the medical community agreed with Darwin and did not think the appendix was necessary and that it had no impact on a person's health unless it became infected or inflamed.

Multiple Theories

In recent years, the medical community has learned more about the appendix. Multiple theories have emerged about the function of the appendix and what it may do in the human body.

One theory is that the appendix stores good gut bacteria that help digestion, support the immune system, and keep bad bacteria in check. If you have diarrhea or another digestive disorder that wipes out your good bacteria, the good bacteria can leave the appendix to repopulate the gut.

Another theory is that the appendix has immune system cells that work to recognize and respond to disease-producing organisms and toxins. These immune cells may protect you from bacterial infections.

Health Problems Related to the Appendix

Inflammation and infection can affect the appendix. This may lead to appendicitis.

Your appendix can also become blocked because of:

  • Hard stool
  • Enlarged tissues inside the appendix
  • Parasites or intestinal worms
  • Objects you eat and cannot digest

Appendicitis Symptoms

Appendicitis is inflammation that happens inside your appendix. If you suspect you may have appendicitis, it is considered a medical emergency. You should seek medical care right away.  

The symptoms of appendicitis include: 

  • Loss of appetite
  • Nausea
  • Vomiting
  • Constipation or diarrhea
  • Fever
  • Abdominal (belly) bloating and swelling
  • Stomach pain that starts in the belly button area and moves to the lower right area
  • Stomach pain that does not go away and becomes worse over time
  • Stomach pain that becomes worse if you walk, sneeze, or cough

Get Emergency Medical Help

Appendicitis is a medical emergency. You need to see a healthcare provider or go to an emergency room immediately when symptoms develop.

Effectiveness of Surgery vs. Antibiotics

To treat appendicitis, your healthcare provider may choose from surgery or antibiotics. Surgery may be necessary to remove the appendix and prevent it from bursting. A burst appendix can spread infection throughout your body and may lead to severe illness or death.

In some cases, your healthcare provider may give you antibiotics to treat appendicitis if there is a low risk of the appendix bursting. Antibiotics can be just as effective as surgery to treat appendicitis, but they can only be used in cases that are not severe.

Aftercare and Recovery

If you have surgery for appendicitis, your surgeon will give you specific instructions to follow at home. In general, you may need to:

  • Avoid strenuous activities, like jogging.
  • Avoid lifting heavy objects for two weeks.
  • Avoid taking baths until your surgeon says you can.
  • Rest when you feel tired.
  • Get enough sleep.
  • Take short walks.
  • Drink plenty of water.
  • Take any medicines prescribed.


The appendix is a small organ located in your lower right abdomen. For centuries, the medical community believed it served no purpose and had no function. In recent years, multiple theories about the function of the appendix have circulated. Research is ongoing to determine any role the appendix may have in gut health.

A Word From Verywell

If you suspect you have appendicitis, seek help right away. Appendicitis is a medical emergency that requires fast diagnosis and treatment. Reach out to your healthcare provider and go to the emergency room to get care.

Frequently Asked Questions

  • Is the appendix useless?

    No, the appendix is not useless. Recent research shows that the appendix is an important organ that affects your immune system and gut health. Scientists continue to learn more about the appendix.

  • Do probiotics do anything for the appendix?

    It is not clear from recent research if probiotics (friendly bacteria normally present in the digestive tract) can have a direct impact on your appendix. However, probiotics may help digestive health in specific circumstances and may lower the risk of diarrhea caused by antibiotics.

  • What can you do to promote a healthy appendix?

    To promote the general health of your large intestine and appendix, you may want to:

    • Eat a healthy diet with plenty of fiber
    • Drink enough fluids
    • Exercise regularly
5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. MedlinePlus. Appendicitis.  

  2. Killinger B, Labrie V. The appendix in Parkinson’s disease: from vestigial remnant to vital organ? J Parkinsons Dis. 2019;9(s2):S345-S358. doi:10.3233/JPD-191703

  3. Vitetta L, Chen J, Clarke S. The vermiform appendix: an immunological organ sustaining a microbiome inoculum. Clin Sci (Lond). 2019;133(1):1-8. doi:10.1042/CS20180956

  4. Salminen P, Paajanen H, Rautio T, et al. Antibiotic therapy vs appendectomy for treatment of uncomplicated acute appendicitis: the APPAC randomized clinical trial. JAMA. 2015;313(23):2340-2348. doi:10.1001/jama.2015.6154

  5. Su G, Ko C, Bercik, P, ET al. AGA clinical practice guidelines on the role of probiotics in the management of gastrointestinal disordersGastroenterology. 2020;159(2):697-705. doi:10.1053/j.gastro.2020.05.059

By Lana Bandoim
Lana Bandoim is a science writer and editor with more than a decade of experience covering complex health topics.