The effect of ether, alcoholic and water extracts of black myrobalan (Teminalia chebula Retz) on Helicobactor pylori were examined using an agar diffusion method on Columbia Agar. Water extracts of black myrobalan showed significant antibacterial activity and had a minimum inhibitory concentration (MIC) and minimum bacteriocidal concentration (MBC) of 125 and 150 mg/l, respectively. The extract was active after autoclaving for 30 min at 121 degrees C. Plant powder (incorporated in agar) gave higher MIC and MBC values (150 and 175 mg/l, respectively). Water extracts of the black myrobalan at a concentration of 1-2.5 mg/ml inhibited urease activity of H. pylori. The results show that black myrobalan extracts contain a heat stable agent(s) with possible therapeutic potential. Other bacterial species were also inhibited by black myrobalan water extracts.