Purpose of appendix believed found

Scientists think they have figured out the real job of the troublesome and seemingly useless appendix: It produces and protects good germs for your gut. For generations doctors figured it had no function. Surgeons removed them routinely and people live fine without them.

In this picture, the appendix is visible at the lower right, labeled as "vermiform process":


According to the new research, the function of the appendix seems related to the massive amount of bacteria populating the human digestive system. There are more bacteria than human cells in the typical body. Most are good and help digest food.

But sometimes the flora of bacteria in the intestines die or are purged. Diseases such as cholera or amoebic dysentery would clear the gut of useful bacteria. The appendix's job is to reboot the digestive system in that case.

The appendix "acts as a good safe house for bacteria" according to scientists. Its location -- just below the normal one-way flow of food and germs in the large intestine in a sort of "gut cul-de-sac" -- helps support the theory.

Also, the worm-shaped organ outgrowth acts like a bacteria factory, cultivating the good germs. That use is not needed in a modern industrialized society, according to the scientists. If a person's gut flora dies, it can usually be repopulated easily with germs they pick up from other people. But before dense populations in modern times and during epidemics of cholera that affected a whole region, it wasn't as easy to grow back that bacteria and the appendix came in handy.