CYP3A4 and cancer: Various studies have shown that piperine inhibit the major hepatic human drug metabolizing enzyme CYP3A4 especially if these drugs are taken by oral administration (Bhardwaj et al., 2002; Singh and Duggal, 2009) For instance, the co-administration of piperine and docetaxel significantly increased the bioavailability of docetaxel and subsequently improved its anti-cancer effect in a xenograft model of human castration-resistant prostate cancer (Makhov et al., 2012).