That is the theory from surgeons and immunologists at Duke University Medical School, published online in a scientific journal this week.
For generations the appendix has been dismissed as superfluous.
Doctors could find no function for it.
Surgeons removed them routinely.
People live fine without them.
And when infected the appendix can turn deadly.
It becomes inflamed quickly, and some people die if it is not removed expeditiously.
Two years ago, 321,000 Americans were hospitalised with appendicitis, according to the Centres for Disease Control and Prevention.
The function of the appendix seems related to the massive amount of bacteria that populates the human digestive system, according to the study in the Journal of Theoretical Biology.
More bacteria inhabit the typical body than human cells.
Most of the bacteria are good and help digest food.
But sometimes the flora of bacteria in the intestines die or are purged.
Diseases such as cholera or amebic dysentery would clear the gut of useful bacteria.
The appendix's job is to reboot the digestive system in that case. - DDNews
