Methanolic extract of H. indicus root (MHI) was screened for its antimicrobial activity against S. typhimurium, E. coli and S. flexneri, in vitro and in experimentally induced diarrhoea in albino rats, in vivo. MHI had an anti enterobacteriae effect as evident from agar well diffusion method and decrease in CFU/ml in MHI treated LB broth culture. MHI inhibited the castor oil induced diarrhoea in rats as judged by a decrease in the amount of wet faeces in MHI-pretreated rats at a dose of 500-1500 mg/kg. The results indicated that MHI was more active than standard antidiarrhoeal drug, lomotil. Phytochemical tests revealed the main constituents as tannins, steroids, triterpenoids and carbohydrates. Present findings suggested that MHI might elicit an antidiarrhoeal effect by inhibition of intestinal motility and by its bacteriocidal activity.