The vaginal flora plays a vital role in preventing the colonization by undesired organisms, including those responsible for Bacterial Vaginosis and Candidiasis (Thrush), urinary tract infections, and sexually transmitted infections. 

In women of childbearing age, the vaginal ecosystem is dominated by the Lactobacillus species, along with an array of other diverse bacteria which are present in much lower numbers. Lactobacilli – lactic acid bacterial – are named after their ability to produce lactic acid, bacteriocins, and hydrogen peroxide. The production of lactic acid stabilises and maintains the acidic environment of the vagina. This metabolite thus becomes the most important protector against pathogenic and opportunistic organisms, which in most cases account for Bacterial Vaginosis.