In line with the topic of this special issue, we studied the cytotoxicity of the aqueous plant extracts (infusions) toward a panel of liver (HepG2), colon (Caco2) and skin (B16-F10) cancer cells as well as their effects upon selected mechanisms of drug resistance in cancer cells, namely, the efflux of xenobiotics by P-gp (Ozben, 2006), and the ability to inhibit tyrosinase-mediated melanogenesis and melanoma migration capacity (Pinon et al., 2011). This evidence concerns the gene PGP and cancer.