The extracts of different plant parts of Schumacher ia were subjected to several chromatographic fracti onations. These extracts yielded fifteen known compounds whos e structures revealed that all three species contai ned taraxerol, betulinaldehyde, betulinic acid, β -sitosterol, 3-O- α -L-arabinosyloleanolic acid and β -sitosterol-3-O- β -D- glucopyranoside; the extracts of S. angustifolia an d S. alnifolia gave betulin; betulonic acid, (6 β )-6-hydroxy-3- oxolup-20(29)-en-28-oic acid, sorbifolin and epicat echin were only found in the extracts of S. castane ifolia. Kaempferol, 7-O-methylkaempferol, catechin and gall ocatechin were isolated from the extracts of S. ang ustifolia. Bioactivity determination of these compounds reveal ed that (6 β )-6-hydroxy-3-oxolup-20(29)-en-28-oic acid exhibited antibacterial activity against both S. au reus and E. coli; 3-O- α -L-arabinosyloleanolic acid showed antibacterial activity and toxicity to brine shrimp s. The genus Dillenia was found to be closely relat ed to the genus Schumacheria because of the presence of oleanene-ty pe triterpenoids.