Inulin is a soluble fiber and fructooligosaccharide ( FOS ) that acts as a prebiotic and improves gut health by stimulating the beneficial bacteria in the gut. Swanson's new Inulin Powder, derived from chicory, is a perfect addition to your favorite meals. You can use it as a thickener and sweetener. In other words: the possibilities are endless and the benefits are truly enormous.