In the centaury herb collected from natural sites in eastern Poland the total content of flavonoids (0.28%), phenolic acids (2.50%) and tannins (1.25%) were determined. From the methanol extract of the raw material four flavonoid compounds were isolated and identified as quercetin 3,3'-dimethylether, kaempferol 3-0-neohesperidoside, isorhamnetin 3-0-glucoside and kaempferol 3-0-rhamnoside-7-0-rutinoside. The last-mentioned compound seems to be a unique one. On the basis of GC of isolated fractions of free phenolic acids and those revealed after alkaline and acid hydrolysis, thirteen phenolic acids were identified. In the fraction of free phenolic acids the main compounds were: protocatechuic, vanillic, p-hydroxybenzoic, m-hydroxybenzoic and syringic acids. In the fraction obtained after alkaline hydrolysis the dominant acids were p-hydroxybenzoic and p-coumaric one. The first one was also the principal acid among those revealed after acid hydrolysis.