10.22376/ijpbs.2019.10.1.p1-12 Volume 6 Issue 4 2015 (October - December) The present study aimed at evaluating lessThan i greaterThan in vitro lessThan /i greaterThan antibacterial activity of flower and stem extracts of lessThan i greaterThan Chrysanthemum coronarium lessThan /i greaterThan in methanolic and acetone solvents by soaking and soxhlet method. The antibacterial activity was evaluated using the agar well diffusion method at four different concentrations (ie 2,3,4 and 5 mg/ml). DMSO was used as a solvent to dissolve the extracts and Ampicillin as a positive control. The extracts were tested against two gram positive ( lessThan i greaterThan S.aureus lessThan /i greaterThan and lessThan i greaterThan B.subtilis lessThan /i greaterThan ) and gram negative bacteria ( lessThan i greaterThan P. aeruginosa lessThan /i greaterThan and lessThan i greaterThan E.coli) lessThan /i greaterThan . All the extracts showed a good inhibitory activity against the gram positive bacteria lessThan i greaterThan (S.aureus lessThan /i greaterThan and lessThan i greaterThan B.subtilis). lessThan /i greaterThan The highest antibacterial activity was shown by methanolic hot extract of lessThan i greaterThan C. coronarium lessThan /i greaterThan stem against lessThan i greaterThan B. subtilis lessThan /i greaterThan (36mm) and the lowest was shown by the acetone cold extract stem against lessThan i greaterThan E.coli lessThan /i greaterThan (13mm) . The antibacterial activity against both type of bacteria indicated broad spectrum of secondary metabolites. Hence it can be used as a therapeutic drug to inhibit bacterial pathogens. SHYLA .M. HAQQ AND POONAM PRAKASH DMSO (Dimethyl sulphoxide), agar well diffusion , Ampicillin, Chrysanthemum coronarium 411-414