AIM: To investigate the bactericidal and anti-adhesive properties of 25 plants against Helicobacter pylori (H pylori).METHODS: Twenty-five plants were boiled in water to produce aqueous extracts that simulate the effect of cooking. The bactericidal activity of the extracts was assessed by a standard kill-curve with seven strains of H pylori. The anti-adhesive property was assessed by the inhibition of binding of four strains of FITC-labeled H pylori to stomach sections. RESULTS: Of all the plants tested, eight plants, including Bengal quince, nightshade, garlic, dill, black pepper, coriander, fenugreek and black tea, were found to have no bactericidal effect on any of the isolates. Columbo weed, long pepper, parsley, tarragon, nutmeg, yellow-berried nightshade, threadstem carpetweed, sage and cinnamon had bactericidal activities against H pylori, but total inhibition of growth was not achieved in this study. Among the plants that killed H pylori, turmeric was the most efficient, followed by cumin, ginger, chilli, borage, black caraway, oregano and liquorice. Moreover, extracts of turmeric; borage and parsley were able to inhibit the adhesion of H pylori strains to the stomach sections.CONCLUSION: Several plants that were tested in our study had bactericidal and/or anti-adhesive effects on H pylori. Ingestion of the plants with anti-adhesive properties could therefore provide a potent altative therapy for H pylori infection, which overcomes the problem of resistance associated with current antibiotic treatment.