In continuation of our studies on the phytochemical investigation of natural products and evaluation of the biological activities of the isolated compounds, recently we have isolated and characterized two triterpenoids, friedelin (1) and cerin (2) from the bark cork (Quercus suber). Biocidal activities of each of them were tested on some fungi and bacrerial plant pathogens, particularly available in this art of west Bengal, India. In addition phytotoxicity of each of them was also tested on some selected specimens. The results of our investigation were encouraging and will serve a lot to the pharmaceutical chemists.