PreticX Xylooligosaccharide (XOS) Prebiotic Clinically Validated to Nourish Intestinal Flora* Prebiotic Bifido Boost Powder is an advanced prebiotic formula that feeds and encourages the growth of probiotic Bifidobacteria in the gut, helping to support a healthy balance of gut ...PreticX Xylooligosaccharide (XOS) Prebiotic Clinically Validated to Nourish Intestinal Flora* Prebiotic Bifido Boost Powder is an advanced prebiotic formula that feeds and encourages the growth of probiotic Bifidobacteria in the gut, helping to support a healthy balance of gut microflora. * This product features PreticX , a unique xylooligosaccharide (XOS) prebiotic ingredient that nourishes existing probiotic bacteria, favorably changing gut microflora composition to promote healthy, balanced immune system function, regularity and intestinal comfort. * This product is sold by weight not volume.