ANTIMICROBIAL ACTIVITY OF CHOSEN MEDICINAL HERBS AND SIDDA DRUGS R. CAROLINE JEBA 1 & G. RAMESHKUMAR 2 1 Department of Industrial Biotechnology, Dr. M. G. R Educational and Research Institute University, Maduravoyal, Tamil Nadu, India 2 Arvind Remedies Ltd, Sidco Industrial Estate, Kakkalur, Tiruvallur, Tamil Nadu, India ABSTRACT The objective of this research was to evaluate the potential at plant extracts and phytochemicals on standard microorganism strains as well as multi-drug resistant bacteria and to study the synergistic effects of extracts with antimicrobial activity in association with antibiotics against drugs resistant bacteria. Antimicrobial activity of the medicinal herbs were found to satisfactory towards the microbes of investigation. Thirteen samples of Indian medicine and siddha drugs were taken for investigation and microbial and biochemical tests were carried out to ascertain the antimicrobial activity. Thirteen samples were I. Sanda magudam Agasthiar, Pandu vaipu 600 II. Karuvangachunnam vadavaidiyathuk III. Upregha sunnam Anuyoga vaidiya navaneetham Abdulla IV. Neelakandar Senduram Pulasthiar vagana soothiram 300 V. Thalisa pathiri sooranam A. Tansil Sooranam B. Kilingal Mezhugu C. Sarndha Kirudhaya Mathirai D. Nochi E. Thayir Sundi Sooranam F. Sitharathai G. Padikaliska Sendooram H. Sedhilpadai Sooranam These thirteen samples were subjected to various microbial and biochemical tests as follows and finally the data is interpreted;  Sterility testing and aseptic techniques.  Determination and classification of bioburden, microscopy.  Screening of pathogen International Journal of Bio-Technology and Research (IJBTR) ISSN 2249-6858 Vol. 3, Issue 3, Aug 2013, 5-18 © TJPRC Pvt. Ltd.