Gut microbiota (GMB) occupy the body at birth with the newborn swallowing microbacteria from the birth canal, and evolve with aging. Bacteria make up most of the gut microorganisms and up to 60% of the dry fecal mass. The GMB is consist of of ~100 trillion bacteria, 10-fold the number of cells in the human body. The collective genome of these bacteria (microbiome) is 150-fold larger than the human genome. Whereas, the preservation of normal microbiota is encouraged by lower modulatory levels of controlling T cells secreting IL-10 and transforming growth factor beta (TGFβ), which decrease inflammation [22]. In addition, the mutualistic reaction to be related to a variability of regulatory T-cells subsets in a real-life gut flora, inclusive of symbiotic, commensal with the probable to become pathogenic, and pathogenic microorganisms. In that complicated situation, Bacteroidetes species reduce intestinal inflammation and promote regulatory T cells induction. However, these replies support the preservation of self-tolerance, and suggest a key role of probiotics in preserving a healthier intestinal microbiota.