We determined the content of biologically active compounds in the bark of seven Rhamnus L. and two Frangula Mill. species growing in Croatia. All taxa tested had high content of total polyphenols (from 2.68% in R. orbiculata Bornm. to 8.50% in R. pumila Turra), moderate content of glucofrangulins (from 0.22% in R. pumila to 9.26% in R. fallax Boiss.), nontannic polyphenols (from 0.73% in R. orbiculata to 5.92% in F. alnus Mill.) and tannins (from 1.10% in R. saxatilis Jacq. to 4.92% in R. alaternus L.), and low content of phenolic acids (from 0.44% in R. orbiculata to 1.81% in R. intermedia Steud. & Hochst.) and flavonoids (from 0.02% in F. alnus to 1.44% in R. pumila). By ANOVA, variability was highest for glucofrangulin content, less for flavonoids, phenolic acids and nontannic polyphenols, and least for total polyphenols and tannins.K Ke ey y w wo or rd ds s: : Rhamnus, Frangula, glucofrangulins, phenolic compounds, quantitative analysis.