Cinchonidine is 8-epi-Cinchonan in which a hydrogen at position 9 is substituted by hydroxy (R configuration). A diasteroisomer of cinchonine, it occurs in the bark of most varieties of Cinchona shrubs, and is frequently used for directing chirality in asymmetric synthesis. It has a role as a metabolite. It is a cinchona alkaloid and an (8xi)-cinchonan-9-ol. It derives from a hydride of an (8S)-cinchonan.