Probiotics (Greek: for life) are commonly defined as mono- or mixed cultures of live microbes that, when applied to animal or human, possess a beneficial effect on health of the host. These beneficial effects include disease treatment and prevention as well as improvement of nutrients’ digestion and absorption. Probiotic microorganisms are generally, albeit not exclusively, lactic acid bacteria (LAB) including Lactobacillus acidophilus, L. bulgaricus, L. casei, L. plantarum, and L. rhamnosus. However, use of other bacterial species such as Bacillus and Bifidobacterium spp. as probiotic strains has also been described in several commercial products. This article intends to present an up-to-date version regarding probiotics, strains currently used and health benefit obtained from their consumption.