OM-85 significantly reduces RTIs in children. This effect was proved by many clinical studies and meta-analyses. A Cochrane meta-analysis first published in 2006 and updated recently (Del-Rio-Navarro 2012) showed that immunostimulants (IS) could reduce acute RTIs (ARTIs) by almost 39% when compared to placebo. Among the different IS, OM-85 showed the most robust evidence with 4 trials of "A quality" according to the Cochrane grading criteria. Pooling six OM-85 studies, the Cochrane review reported a mean number of ARTIs reduction by -1.20 [95% Confidence Interval (CI): -1.75, -0.66 ] and a percentage difference in ARTIs by -35.9% [95% CI: -49.46, -22.35 ] compared to placebo.