10.22376/ijpbs.2019.10.1.p1-12 Volume 2 Issue 2 2011 (April - June) The objective of the present study was to assess the anti bacterial activity of lessThan i greaterThan Acacia catechu lessThan /i greaterThan lessThan i greaterThan willd lessThan /i greaterThan (AC). AC is a moderate sized deciduous tree growing in tropical countries commonly called "Karungali" in Tamil. It is a potent medicinal plant in the traditional Indian medicinal systems. Aqueous and ethanolic extract of Heartwood of lessThan i greaterThan Acacia catechu lessThan /i greaterThan is tested for antibacterial activity against lessThan i greaterThan Staphylococcus aureus lessThan /i greaterThan , lessThan i greaterThan Bacillus subtilis lessThan /i greaterThan , lessThan i greaterThan E.coli lessThan /i greaterThan , lessThan i greaterThan Pseudomonas aeruginosa, Klebsiella pneumoniae lessThan /i greaterThan . Disc diffusion technique was followed for screening anti bacterial activity. The discs were loaded with 50µl of aqueous and ethanolic extracts at different concentrations. Positive controls used were Amoxycillin (30 µg/disc) and Ciprofloxacin (5 µg/disc). After incubation at 37ºc over night, the zone of Inhibition was measured. Ethanolic extract showed significant activity than Aqueous extract against the micro organism compared to standard lessThan b greaterThan . lessThan /b greaterThan Lakshmi T.,Geetha R. V. And Anitha Roy Acacia catechu willd, Anti bacterial evaluation, Mac Farland’s standard, Zone of inhibition. 188-192