10.22376/ijpbs.2019.10.1.p1-12 Volume 6 Issue 1 2015 (January - March) The antibacterial activities and phytochemical analysis of crude extracts of four indigenous plants ( lessThan i greaterThan Acorus calamus, Euphorbia hirta, lessThan /i greaterThan lessThan i greaterThan Solanum surattense lessThan /i greaterThan and lessThan i greaterThan Taxus baccata lessThan /i greaterThan ) grown in Garhwal Hills region of western Himalaya, India were tested against pathogenic lessThan i greaterThan  Escherichia coli, Staphylococcus aureus lessThan /i greaterThan , lessThan i greaterThan Klebsiella lessThan /i greaterThan lessThan i greaterThan pneumoniae, Staphylococcus epidermidis, lessThan /i greaterThan and lessThan i greaterThan Bacillus cereus lessThan /i greaterThan . Solvent extraction of investigated plants parts was performed using ethanol, methanol, ethyl acetate, hexane, aqueous and chloroform. Determination of the antibacterial activities revealed that aqueous, methanol and ethanol extracts of lessThan i greaterThan Acorus calamus lessThan /i greaterThan and lessThan i greaterThan Euphorbia hirta lessThan /i greaterThan significantly inhibited most of the pathogens while, in case of lessThan i greaterThan Taxus baccata lessThan /i greaterThan and lessThan i greaterThan Solanum surattense lessThan /i greaterThan solvent extracts moderately suppressed the pathogens. Minimum inhibitory concentration (MIC) values calculated for lessThan i greaterThan Solanum lessThan /i greaterThan ranged 80 mg/ml–100 mg/ml. lessThan i greaterThan Taxus lessThan /i greaterThan leaves MIC range were fell between 20 mg/ml – 60 mg/ml. lessThan i greaterThan A. calamus lessThan /i greaterThan gave lowest and most promising MIC value of 6 mg/ml against lessThan i greaterThan S. auerus lessThan /i greaterThan and 8 mg/ml against both lessThan i greaterThan K. lessThan /i greaterThan lessThan i greaterThan pneumoniae lessThan /i greaterThan and lessThan i greaterThan E. coli lessThan /i greaterThan , however, the zones of inhibitions were also on lower side and lessThan i greaterThan Euphorbia hirta lessThan /i greaterThan measured MIC range of 25 mg/ml – 100 mg/ml. Phytochemical analysis of these plants recorded presence of almost all major phytonutrients. The research outcome leads to conclusion that these four plants extracts possess antimicrobial activity against human pathogenic bacterial strains. RENU NEGI AND SUMAN BISHT Antimicrobial activity, Minimum inhibitory concentration, Zone of inhibition, Western Himalayan Garhwal hills 692-699