Flexi Says: The appendix is a part of the large intestine. The function of the appendix is to act as a storehouse for good bacteria for rebooting the natural microflora of the intestine from time to time. Some experts believe the appendix is just a useless remnant from our evolutionary past when we used to eat raw food. However, newer research indicates that the appendix contains lymphoid tissue and plays a role in immunity. Early in development, the appendix produces certain types of antibodies and helps to produce certain white blood cells. A related appendix function may be to expose white blood cells to the wide variety of antigens (foreign substances) present in the gastrointestinal tract so that the immune system can develop necessary responses.