Aim: To evaluate whether eradication of Helicobacter pylori prevents peptic ulcer in non-steroidal anti-inflammatory drug users by means of a meta-analysis. Material and methods: A systematic search was performed in MEDLINE, EMBASE, the Cochrane Controlled Trials Register and the AGA congress. Randomized trials comparing H. pylori eradication vs. non-eradication or eradication vs. a proton pump inhibitor in patients receiving a non-steroidal anti-inflammatory drug were selected. Results: Five studies and 939 patients were included in the analysis; 34 of 459 (7.4%) patients developed a peptic ulcer in the eradicated group vs. 64 of 480 (13.3%) in the control group. The odds ratio was 0.43 (95% confidence interval: 0.20-0.93). Sub-analyses showed a significant reduction of risk for non-steroidal anti-inflammatory drug-naive (odds ratio = 0.26; 95% confidence interval: 0.14-0.49) but not for previously treated patients (odds ratio = 0.95, 95% confidence interval: 0.53-1.72). Two studies with a total of 385 patients compared eradication vs. a proton pump inhibitor; five of 196 (2.6%) developed a peptic ulcer in the eradicated group vs. zero of 189 (0%) in the proton pump inhibitor group (odds ratio = 7.43; 95% confidence interval: 1.27-43.6). Conclusion: Helicobacter pylori eradication reduces the incidence of peptic ulcer in the overall population receiving non-steroidal anti-inflammatory drugs. It appears to be especially effective when performed in non-steroidal anti-inflammatory drug-naïve patients. Nonetheless, eradication seems less effective than treatment with a maintenance proton pump inhibitor for preventing non-steroidal anti-inflammatory drug-associated ulcers. © 2005 Blackwell Publishing Ltd.