Three microorganisms causing gastroenteritis were used for the study of the antibacterial effects of <I>Phyllantus niruri, </I>extracts. The bacterial pathogens used were <I>Escherichia coli, Staphylococcus aureus </I>and <I>Salmonella typhi. </I>The solvents used for the extraction of active components of the plant (whole plant) were hot water, cold water (both as aqueous solvent) and ethanol. The antibacterial effect of the plant extracts showed that all the extracts were inhibitory to <I>E. coli, S. aureus </I>and S. <I>typh</I>i. The results of the Minimum Inhibitory Concentration (MIC) value of the extracts on the organisms are 31.25 mg mL for <I>S. aureu</I>s, 15.625 mg mL for <I>E. coli </I>and 31.25-62.50 mg mL for S. <I>typh</I>i. !The pathogens used were not multi-drug resistant strains to most of the orthodox drugs. The antibacterial effect of plant extracts of <I>P. niruri </I>tends to give a clue to the problem of drug resistant strains of microorganisms causing gastroenteristis and thus provides the possibility of drug development for such human diseases.