Abstract: The nutritional value of diary based product that contains probiotic bacteria on the gastrointestinal health and functions have been investigated in this study. Both probiotic Lactobacillus bulgaricus and Streptococcus thermophilus species, contribute to the formation of yogurt as a result of anaerobic fermentation of lactic acid in the milk. The benefits of yogurt consumption on the gastrointestinal function mediated through the gut micro flora, bowel transit and the enhancement of gastrointestinal immune responses. Numerous studies suggested beneficial therapeutic effect of probiotic bacteria in the yogurt and other fermented dairy products on the gut health. Certain disease with gastrointestinal tract such as, lactose intolerance, diarrhea, colon Cancer, inflammatory bowel disease and other bacterial infection were inhibited through high consumption of yogurt. Probiotic bacteria can protect against enteric infection and inhibit chemically Carcinogens induce tumorization in the gastrointestinal tract. Modulation of the gut microflora and the enhancement of mucosal immunity of the gut are both mechanisms of probiotic function potentially influence gut function. Combination of Probiotic active culture and prebiotics non digestible food ingredient, beneficially affect the host by improving the survival of live microbial dietary supplement through its transit in the gut and by stimulating the activity of colon bacteria, specially Bifidobacteria and Lactobacilli genera. Further well-designed, controlled animal studies are needed to confirm the effects of different sources of probiotic strains used in the diary products, on gut health and function.