10.22376/ijpbs.2019.10.1.p1-12 Volume 4 Issue 1 2013 (January - March) The methanolic, aqueous and chloroform extracts of the endemic medicinal plant species of lessThan i greaterThan Caralluma nilagiriana lessThan /i greaterThan were studied for antibacterial activities against five microorganisms. The zone of inhibition of various extracts was compared with standard tetracycline(30µg/ml). The antibacterial activity justifies its use in traditional medicine. In lessThan i greaterThan Salmonella typhi lessThan /i greaterThan lessThan i greaterThan . Escherichia. coli lessThan /i greaterThan , and lessThan i greaterThan Staphylococcus aureus lessThan /i greaterThan all the three extracts(30µg/ml) was found to have significant antimicrobial activity, but less than that of standard tetracycline. In lessThan i greaterThan Klebsiella pneumonia lessThan /i greaterThan all the three extracts were highly active when compared to standard. But in lessThan i greaterThan Pseudomonas aeroginosa lessThan /i greaterThan the methanolic extracts strongly inhibited the colonial growth against the standard.The other two extracts found to have antimicrobial potency but less than that of standard. R.PRABAKARAN, AND K.KALIMUTHU Caralluma nilagiriana, tetracycline, antimicrobial activity. 42-48