After the strong highlight of SECO as an inhibitor of P-gp efflux transporter by in silico studies, in vitro experiments were done for confirmation and showed that SECO at a dose of 25 or 50 μM inhibited P-gp induced efflux of rhodamine-123 and increased its intracellular accumulation in NCI/ADR-RES cancer cells. This evidence concerns the gene PGP and cancer.