A total of 34 plant species belonging to 18 different families, selected on the basis of folklore medicinal reports practised by the tribal people of Western Ghats, India, were assayed for antibacterial activity against Escherichia coli, Klebsiella aerogenes, Proteus vulgaris, and Pseudomonas aerogenes (gram-negative bacteria) at 1000-5000 ppm using the disc diffusion method. Of these 16 plants showed activity; among them Cassia fistula, Terminalia arjuna and Vitex negundo showed significant antibacterial activity against the tested bacteria. Our findings confirm the traditional therapeutic claims for these herbs.