Antibacterial compounds of Conkerberry Root of the plant Carissa lanceolata R.Br. has been used as a medicinal plant by Aboriginal people of Australia. The uses are particularly of conditions targeting bacterial infections, thus suggesting a potential antibacterial activity. Initially the root bark was studied for the essential oil composition, to find out that it comprise of one single volatile substance with very effective antibacterial activity. Root was further extracted with different solvent s of ascending polarity. Three eudesmane- type sesquiterpene and a lignan carinol were identified and there antibacterial activity was established. Chemical structures of these compounds were elucidated by different spectroscopical methods. Two other yet unidentified compounds were isolated, but further studies on their chemistry and antibacterial activity were not possible in the framework of the current study.Though this research was aimed in studying the chemical properties of antibacterial compounds, it has strongly contributed in establishing the indigenous use of this plant in medicine.