Prebiotin � RD supports overall health, immunity and digestive wellness by nourishing beneficial bacteria and it gives your diet an extra helping of insoluble fiber for a soft, regular stool. Lightly vanilla flavored. Get Wheat Bran, Psyllium (dietary fiber) and prebiotic fiber all in one convenient dose. All natural. NOTE: Contains Gluten. Prebiotin Regularity supplements promote digestive regularity, support digestive health, immunity, bone density and calcium absorption by nourishing beneficial bacteria. It gives your diet a generous boost of fiber too! Prebiotin Regularity supplements offer a full-spectrum prebiotic (Oligofructose-Enriched-Inulin, or OEI). Unlike ordinary prebiotics such as Inulin or FOS, OEI ensures that Prebiotin nourishes beneficial bacteria throughout the colon. OEI is also the most researched prebiotic, used in many university and clinical studies.