RESULTS
The searches identified 33 potentially relevant trials,
15–47 but only 6 double-blind RCTs15–20 met the
aforementioned inclusion criteria and were included in
this systematic review. The flow chart provides an overview
of all included and excluded trials (Fig. 1). The
assessment of their methodological quality revealed a
maximal score for 5 of 6 studies. Four RCTs15–17,19
compared the efficacy of ginger to placebo, whereas 2
trials18,20 compared the efficacy of ginger to vitamin B6
(used as a reference compound). Key data are summa-