Fortification of our diet with certain gut flora components is a popular current aspect of functional food sciences. Lactic acid bacteria (LAB) are normal components of the healthy human intestinal microflora, are commonly used as probiotics added to food products mainly because of their supposed health-promoting activities. Probiotics are live microbial additions to the diet; prebiotics are foodstuffs that have a selective metabolism in the hindgut, whilst synbiotics are combinations of the two approaches. Developments in the application of probiotics as potential therapeutics i. e. treatment of infections, for controlling HIV and as novel vaccine delivery vehicles. This text recapitulated findings and safety issues related to LAB are promising biological agents that can be used as probiotics.