Some 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.

That's 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 figured it had no function. Surgeons removed them routinely. People live fine without them.

The appendix "acts as a good safe house for bacteria," said Duke surgery professor Bill Parker, a study co-author. 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, he said.