The antimicrobial activity of 100 extracts of twenty plants Namely Symplocos racemosa, Solanum xanthocapum, Phyllanthus urinaria, Blumea lacera, Acorus calamus, Thevetia nerifolia, Bauhinia purpurea, Jatropha gossypifolia, Pithecellobium dulce, Hydrangea integrifolia, Sphaeranthus indicus, Vitex negundo, Zizyphus xylopyrus, Aconitum heterophyllum, Scoparia dulcis, Callicarpa dichtoma, Adhatoda zylamei, Sphaeralcea angustifolia, Swertia chirayita, Aconitum heterophyllum from Uttar Pradesh, India was tested against twelve pathogenic micro-organisms. The 51 extracts of P. urinaria, B. lacera, B. eriantha, T. nerifolia, J. gossypifolia, P. dulce, H. integrifolia, S. indicus, V. negundo, Z. xylopyrus, A. heterophylum, S. dulcis, C. dichtoma, A. zylamei, S. angustifolia, S. chirayita, A. heterophyllum were found to be inhibiting all the bacterial strains tested, in a range of concentrations by microbroth dilution assay and 0.75 to 48.0 mg/disc by disc diffusion assay. The 37 extracts were found to be active against the fungal strains in arrange of 0.75 to 24.0 mg/ml by microbroth dilution assay. Other plant extracts also exhibited variable antimicrobial activity against one or more species of microorganisms. As the extracts of all the plants which were used in this study effectively controlled the growth of many pathogenic bacteria and fungi, they can be used in the treatment of various infectious diseases. Bioactive compounds from these plants can be employed in the formulation of antimicrobial agents for the treatment of various bacterial and fungal infections.