Previously, appendix is known to have no function in the human body or if it has function it is unknown. Aside from being useless it can also cause illness when a person's appendix become inflamed or even rupture. But a new research reinforced the idea that it may serves as a storehouse for good bacteria, rebooting the digestive system after diarrheal illness.

Associate Professor at Midwestern University Arizona College of Osteopathic Medicine Heather F. Smith has observed in her new research, published in the journal Comptes Rendus Palevol, the presence or absence of appendix from 533 different mammals. She noticed how gastrointestinal traits evolved across different animal species,

She discovered that more than 30 separate times the appendix evolved independently in different genetic in what science called "trees". Once it appeared from a lineage it almost never disappeared. That's why the organ remains for an adaptive purpose.

Smith together with co-authors from Duke University Medical Center, University of Stellenbosch in South Africa and the Museum National d' Histoire Naaturelle in France disregard some previous theories that appendix may serve for dietary or environmental factors.

According to Time, the discovery that strengthen the past idea that appendix serves as a storehouse for beneficial bacteria is the difference of species with appendix from species without. Species with appendix have higher concentrations of lymphoid tissue in their cecum, the pouch that serves as connection to small and large intestine.

Lymphoid tissue has something to do with immunity, and can help the growth of healthy gut bacteria. So Smith concluded that it really serves as safehouse for these friendly bugs.

Smith's appendix herself was removed when she was 12. She said that without appendix already may not cause too much effect. Since appendix is related to immunity, people without it may just have little bit higher of infection than those with. When they have sickness they might not recover immediately, Smith said.

This discovery may help doctors in the future to address appendix common problems. "As treatments are developed for other autoimmune disorders and responses, it's certainly possible that something similar may be developed for treating appendicitis," she says.