A preliminary investigations was carried out to study the antibacterial activity of the water soluble extracts of five and ten years old barks of Eugenia Jambolana Lam. (fam. Myrtaceae) on dysentery and diarrhoea forming micro organisms. It was observed that the barks of young plants have a better inhibitory effect on micro - organisms like Salmonella viballerup, Shigella dysenteriae 10, Shigella boydii 5, Sgigella dysenteriae 2.