C2 Adamantanyl globotriaosylceramide (AdaGb3) is a bioactive sphingolipid and water-soluble form of globotriaosylceramide that contains an adamantanyl group in place of the fatty acyl chain. It inhibits Vero toxin binding to globotriaosylceramide in an ELISA assay when used at a concentration of 10 μM. AdaGb3 decreases cell surface expression of P-glycoprotein (P-gp) and reduces efflux of rhodamine 123 in MDCK cells. It also increases apical-to-basal transport of vinblastine in human intestinal C2BBe1 cells.