Recently, the use of probiotics by human beings through different delivery routes is increased. These are those microorganisms that produce positive health benefits to the host. Different species of probiotics are used in human food matrices, but the commonly used probiotics are related to Bifido-bacteria and Lactobacillus genus. The health benefits attributed to probiotic consumption are investigated in numerous human and animal studies. These benefits are the improvement of metabolic disorders like control of diarrhea, improvement in lactose intolerance, prevention of colon cancer, treatment of H. pylori; decrement in blood cholesterol, alleviation in sensitivity and so forth. etc... The mentioned health benefits are species species-dependent. These microorganisms produce the benefits through several mechanisms such as competitive exclusion of pathogens and colonization resistance, normalization of altered microbiota, Anti Anti-proliferative effect, competition for nutrients, production of inhibitory substances, production of short chain fatty acids, and degradation of toxin receptors, immune effects, and regulation of intestinal transit. In this article, information and the results of recently conducted research concerning probiotics, its properties and mechanism of action, and health benefits of probiotics are gathered and discussed.