Scientists at the Walter and Eliza Hall Institute (WEHI) have concluded that the appendix and a group of immune cells join together to ward off digestive infections.

The new findings, led by Professor Gabrielle Belz, a laboratory head at the WEHI's molecular immunology division, give lie to the commonly held belief that the appendix doesn't contribute much to the body's functioning.

"Popular belief tells us the appendix is a liability ... However, we may wish to rethink whether the appendix is irrelevant to our health," she said on Tuesday.

The study, led by Belz and leading French immunologist Professor Eric Vivier, found that innate lymphoid cells (ILCs) shield the appendix from harmful bacteria.

This allows the organ to provide a refuge for the 'good' bacteria before they "reseed" the intestines and bring good health back to the digestive system.

The results of the study, published in Nature Immunology journal on Tuesday, showed the ILCs form an extra layer of protection for the immune system of healthy people.

The study also found the ILCs are able to withstand chemotherapy treatment, which is unusual for immune cells.

With 70,000 Australians getting their appendix removed each year, it is one of the most common medical procedures.

But in recent times, doctors have begun to advise against surgery, which is now regarded as a last resort.