The phytochemical curcumin and phytochemical flavonoids have been described as natural modulators of MDR transporter expression.19,20 Curcumin and its metabolite tertrahydrocurcumin were used in restoring drug sensitivity in cancer cells overexpressing the MDR-linked ABC transporters MRP1,50 Pgp,51 and ABCG252 by directly inhibiting their functions. Here, ABCG2 is linked to cancer.