10.22376/ijpbs.2019.10.1.p1-12 Volume 5 Issue 2 2014 (April - June) Phytochemicals are chemical compounds that occur naturally in plants and protect plants against bacteria, viruses, and fungi. They are non-nutritive plant chemicals that have protective and disease preventive properties.The aim of the present study was to investigate the antibacterial activities of phytochemical extracts from the leaves of Justicia gendarussa. The antibacterial activities of Justicia gendarussa phytochemical extracts were determined by agar disc diffusion and minimum inhibitory concentration (MIC) against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Vibrio cholerae.The highest zone of inhibitory activity was observed with alkaloid extract of the plant against the test bacteria while less antibacterial activity was observed in terpenoid, flavanoid and glycoside extracts. Therefore, it was confirmed that alkaloid extract of Justicia gendarussa containss a high level of antibactericidal compound which can be used as a novel chemotherapeutic drug for bacterial diseases.  A.SIVASAKTHI AND VIJAYALAKSHMI M Justicia gendarussa, Antibacterial activities, Alkaloid extract and novel chemotherapeutic drug. 433-438