Fractionation of the xanthine oxidase inhibitory methanol extract of Conyza bonariensis afforded three glycosides, in addition to nine known compounds including amyrin, b-sitostero1 daucosterol, syringic acid 3-hydroxy-5-methoxybenzoic acid, eugenol 4-Oglucopyranoside, and luteolin, apigenin and takakin 8-O-glucuronide. The structures of the glycosides were established by a combination of spectroscopic methods (IR, MS, 1Hand 13C NMR, DEPT, COSY, HMQC and HMBC) as 4-hydroxypyridin-3-carboxylic acid 4-O-glucopyranoside, 8-hydroxy-6,7-dihydrolinalool 8-O-glucopyranoside and bonaroside [viz. 1,3,4,12-tetrahydroxy-2-(9-hexadecenoylamino) octadecane 1-O-glucopyranoside]. The in vitro enzyme assay showed that syringic acid and takakin 8-O-glucuronide displayed weak inhibitory activity against xanthine oxidase with IC50 values of 500±41μM and 170±12μM, respectively.