The contents of secondary metabolites (alkaloids and anthraquinones) in Cinchona ledgeriana bark infected with Phytophthora cinnamomi and in non-infected bark were determined. It was found that the alkaloid content of the infected bark was lower. Whereas no anthraquinones could be detected in the healthy bark, these compounds were present in the infected bark. So, anthraquinones in Cinchona act as phytoalexins.