In this study Meryta denhamii Seem. fruits (Araliaceae) were tested for the antihyperglycemic effect against alloxan induced hyperglycemia in rats using metformin as standard drug. The alcoholic extract and n-butanol fraction (saponins rich fraction) of the fruits exhibited significant antihyperglycemic effect (42.8 and 38.4 % of change, respectively, comparing to 67.1% for metformin). The n-butanol fraction was subjected to chemical study which resulted in isolation of four monodesmosidic oleanane saponins. Their structures were established based on their MS, 1H-NMR and 13C-NMR spectral data as 3-O-[b-D-glucopyranosyl] oleanolic acid, 3-O-[a-D-glucuronopyranosyl] oleanolic acid, 3-O-[b-Dglucopyranosyl-( 1-3)-a-L-arabinofuranosyl] oleanolic acid and 3-O-[a-L-arabinofuranosyl-(1-4)-b-D-glucuronopyranosyl] oleanolic acid.