Laggera pterodonta (DC.) Sch. Bip. aerial part was extracted successively with hexane, ethyl acetate and methanol. The ethyl acetate extract was subjected to chromatography to give a pentacyclic triterpenoid ester which was identified as taraxasteryl acetate based on spectroscopic evidence. The triterpenoid exhibited antimicrobial activity against Staphylococcus aureus, Klebsiella pneumoniae, Klebsiella ozaenae, Bacillus cereus, Shigella dysenteriae, Escherica.coli and Streptococcus faecalis with MICs ranging from 25-50µg/ml. This is the first time taraxasteryl acetate has been isolated from the genus, Laggera.