
Calotropis has been ethnomedicinally utilized from ancient times. Calotropis leaves were collected from the Campus Playground of Urumu Dhanalakshmi College, Trichy and authenticated through the Rapinat Herbarium, St.Joseph’s college, Trichy. Calotropis leaves were collected dried, powdered and extracted with 80% methanol. The Rhizosphere bacteria of Calotropis was isolated and identified based on their morphological and biochemical characters. Plant extract was tested against the rhizosphere bacteria of Calotropis (Pseudomonas aeruginosa, Eschercia coli, Staphylococcus aureus, Bacillus subtilis) for the antimicrobial activity in Muller – Hinton agar medium at different concentrations.