I have developed probiotic yoghurt that is effectively used against gastrointestinal ailments due to the combined effect of potential probiotic bacteria i-e L. acidophilus, L. bulgaricus and S. thermophilus.All the strains that I finally selected from culture bank of the Food Microbiology Lab remained viable upto 21 days in yoghurt medium even yoghurt whey had antimicrobial effect against pathogenic bacteria.The present study has provided some excellent understanding about the potential of probiotic cultures against pathogenic bacteria and also against desirable ones.In future, one might be in a position to prepare probiotic cultures in more appropriate forms to prepare a more valuable, healthy and functional food at a cheap cost, to be used against various bacterial infections and also be able to earn foreign exchange through the export of starter culture. and the fermented milk products.