Siddha Papers 2019 (14)(1) Priyadharshini et al Siddha Papers 2019 (14) (1) RESEARCH ARTICLE https://www.siddhapapers.com Anti-microbial screening of a Siddha formulation Kottikkizhangu Chooranam (Aponogeton Monostachyon) M. Priyadharshini 1 , K.Vanitha 2 , P.Deepadharshini 2 , P.Gayathiri 2 , A.Ramya 2 , A.Ranjani 2 G.Vandhana sai 2 , Thomas.M.Walter 3 1,2 2 nd Year BSMS, Government, Siddha Medical College, Palayamkottai, dharshinideepa161299@gmail.com 3 Lecturer, Government siddha Medical College and hospital, Palayamkottai, dr.thomaswalter@gmail.com. ABSTRACT Siddha Medicine is the traditional medicine originating in ancient Thamilagam in south India. Eighteen siddhars laid the foundation for this system of medicine. The siddha system is largely therapeutic and prophylactic in nature. The aim of the work is to prove the anti-microbial activity of the Kottikkizhangu chooranam which is mainly indicated for Thaemal (Leucoderma) and Vellai (Leucorrhoea) mentioned in Materia Medica- Siddha. Kottikkizhangu chooranam (Aponogeton monostachyon) is a Siddha formulation. It has Kulirchiundakki (Refrigerant),Uramakki (Tonic) actions. Antibiotic susceptibility tests were determined by Agar disc diffusion (Kirby-Bauer) method. This drug was tested for antimicrobial property against Proteus vulgaris, Staphylococcus aureus, Streptococcus mutans, Bacillus subtilis, Klebsiella pneumoniae, Escherichia coli by Agar disc diffusion methods. Streptomycin is used as a positive control for this study. The results obtained from the study showed that Kottikkizhangu chooranam has antimicrobial property against Streptococcus mutans are more effective. KEYWORDS Kottikkizhangu chooranam, Aponogeton monostachyon Antimicrobial, Siddha formulation. INTRODUCTION Antimicrobial agent destroys or inhibits the growth of microorganisms. Antimicrobial agents from plants are plentiful such as Penicillin, Cycloartenol, Stigmasterol, Fusarubin. Plants produce