Kefiran is a microbial polysaccharide extracted from the flora of kefir grains; the grains are usually used as a starter of a traditional fermented milk product, originally from Caucasian and Eastern European regions. This probiotic is produced by lactic acid bacteria, mainly Lactobacillus kefiranofaciens, and also by yeasts. Moreover, Kefiran has been reported to possess several beneficial on human health, which has contributed significantly to the rising interest of this amazing biopolymer in several countries worldwide (1). Though, its biological characterization has yet to be completely recognized and properly exploited. In this research, we aimed to evaluate by using various in vitro assays the biological properties of Kefiran polysaccharide, particularly its antioxidant property such as reducing power, metal chelating, hydroxyl and superoxide radical scavenging; and its anti-inflammatory property through nitric oxide scavenging in a cell-free system. This exopolysaccharide showed a distinct antioxidant performance in the majority of in vitro working mechanisms of antioxidant activity comparing to HA. Moreover, Kefiran presented an interesting capacity to scavenge nitric oxide radical comparing to the gold standard that did not present any potency. Finally, the cytotoxic effects of Kefiran extracts on hASCs were also performed and demonstrated no cytotoxic response, ability to improve cellular function of hASCs. This study demonstrated that Kefiran represented a great scavenger for reactive oxygen and nitrogen species and showed also that it could be an excellent candidate to promote tissue repair and regeneration.