The phenolic acids constituents of the water extract of the capitula of Coreopsis tinctoria were isolated and purified by many kinds of chromatography.Their structures were identified according to the physical and chemical constants and spectral data as caffeic acid(1),1-O-caffeoyl-β-D-glucopyranose(2),vanilloyl-β-D-glucopyranose(3),5-O-caffeoylquinic acid(4),3-O-caffeoylquinic acid(5),4-O-caffeoylquinic acid(6),3,4-di-O-caffeoylquinic(7),1,5-di-O-caffeoylquinic(8),3,5-di-O-caffeoylquinic(9),4,5-di-O-caffeo...