A systematic review including 11 RCTs with a total of 737 subjects with irritable bowel syndrome or non-ulcer dyspepsia was abstracted in DARE. The pooled OR for improvement on therapy was 4.2 (95% CI 2.3 to 7.9), and the pooled risk difference was 0.32, NNT = 3.2 (95% CI 2.1 to 6.7). There was no heterogeneity, and no evidence of publication bias. Meta-regression found no significant effect of publication year, type of syndrome, or drug type.