The results suggest that piperine analogs at a concentration of 2 μM were more potent than piperine at increasing the sensitivity of P-gp overexpressing KB and SW480 cancer cells to chemotherapeutic drugs vincristine (VCR), colchicine (COL) and paclitaxel (PTX), without affecting the parental KB and SW480 cells. The gene discussed is PGP; the disease is cancer.