Elevated system exposures of baicalin after combinatory oral administration of rhein and baicalin: Mainly related to breast cancer resistance protein (ABCG2), not UDP-glucuronosyltransferases

A traditional Chinese medicine (TCM) prescription follows the principle of compatibility (peiwu) to achieve the fundamental purpose: to increase efficacy and reduce toxicity. Rhei rhizoma, commonly known as Chinese rhubarb, is the most frequently used herb with Radix Scutellariaee. This classic fixed compatibility is considered for heat-clearing, qi regulation and detoxifying to gain better efficacy and reduce cytotoxicity with respect to...