Coupling of UDP-glucuronosyltransferases and multidrug resistance-associated proteins is responsible for the intestinal disposition and poor bioavailability of emodin

► Glucuronidation is the main reason for the poor oral bioavailability of emodin. ► Efflux transporters are involved in the excretion of emodin glucuronide. ► The intestine is the main organ for metabolism of emodin.