Letter to the Editor The Effect of Vitamin C on the Common

Proponents of evidence-based medicine (EBM) emphasize that conclusions about medical interventions should be based on controlled trials with clinically relevant outcomes, so that the greatest weight should be given to the systematic reviews of the trials. One of the most comprehensive EBM databases is the Cochrane Library, which contains thousands of systematic reviews on medical interventions. The Cochrane review on vitamin C and the common cold analyzed 29 trial comparisons on the preventive effects of vitamin C, 29 comparisons on the effect of regular vitamin C on common cold duration and severity, and 7 comparisons on the therapeutic effect of vitamin C.1 The review concludes: ‘‘Implications for practice: The prophylaxis trials found a reduction in common cold duration of 8 % in adults and 13% in children.... So far, therapeutic supplementation has no