It has long been regarded as a potentially troublesome, redundant organ, but American researchers say they have discovered the true function of the appendix.
The researchers say it acts as a safe house for good bacteria, which can be used to effectively reboot the gut following a bout of dysentery or cholera.
The conventional wisdom is that the small pouch protruding from the first part of the large intestine is redundant and many people have their appendix removed and appear none the worse for it.
Scientists from the Duke University Medical Centre in North Carolina say following a severe bout of cholera or dysentery, which can purge the gut of bacteria essential for digestion, the reserve good bacteria emerge from the appendix to take up the role.
But Professor Bill Parker says the finding does not mean we should cling onto our appendices at all costs.