AIM: To assess the safety of bismuth used in Helico- bacter pylori (H pylori) eradication therapy regimens. METHODS: We conducted a systematic review and meta-analysis. MEDLINE and EMBASE were searched (up to October 2007) to identify randomised controlled tri- als comparing bismuth with placebo or no treatment, or bismuth salts in combination with antibiotics as part of eradication therapy with the same dose and duration of antibiotics alone or, in combination, with acid suppres- sion. Total numbers of adverse events were recorded. Data were pooled and expressed as relative risks with 95% confidence intervals (CI). RESULTS: We identified 35 randomised controlled tri- als containing 4763 patients. There were no serious adverse events occurring with bismuth therapy. There was no statistically significant difference detected in total adverse events with bismuth [relative risk (RR) = 1.01; 95% CI: 0.87-1.16], specific individual adverse events, with the exception of dark stools (RR = 5.06; 95% CI: 1.59-16.12), or adverse events leading to withdrawal of therapy (RR = 0.86; 95% CI: 0.54-1.37). CONCLUSION: Bismuth for the treatment of H pylori is safe and well-tolerated. The only adverse event oc- curring significantly more commonly was dark stools. AIM: To assess the safety of bismuth used in Helico-bacter pylori (H pylori) eradication therapy regimens. METHODS: We conducted a systematic review and meta-analysis. MEDLINE and EMBASE were searched (up to October 2007) to identify randomly-controlled triad - als comparing bismuth with placebo or no treatment, or bismuth salts in combination with antibiotics as part of eradication therapy with the same dose and duration of antibiotics alone or, in combination, with acid suppres- sion. Total numbers of adverse events were recorded. There were no serious adverse events occurring with bismuth therapy. There were no statistically significant difference detected in total adverse events with bismuth [relative risk (RR) = 1.01; 95% CI: 0.87-1.16], specific individual adverse events, with the exception of dark stools (RR = 5.06 ; 95% CI: 1.59-16.12), or adverse events leading to withdrawal of therapy (RR = 0.86; 95% CI: 0.54-1.37). CONCLUSION: Bismuth for the treatment of Hpylori is safe and well-tolerated. The only adverse event oc- curring significantly more was dark stools.