Clinical studies are necessary to establish the safety and effectiveness of all medicines including traditional Chinese medicine (TCM) (Tang et al., 1999; Zhang et al, 2012). So far, most evidence on the safety and efficacy of TCM has been derived from randomized controlled trials (RCTs), which are designed to answer specific scientific and health care questions (Jiang et al., 2010), but these may not necessarily reflect clinical practice. Although RCTs form the foundation of evidence-based medicine (EBM), such studies can be relied upon only if they are conducted according to good practice (Guyatt and Rennie, 2002). Despite the controversy associated with EBM (Des, 2014), the hierarchy of evidence indicates the relative weight and value of evidence. Systematic reviews (SRs) and meta-analyses, which synthesize the results of a number of similar studies, produce results with greater statistical power and are thought to be more robust. Nevertheless, SRs and meta-analyses depend on the quality of the original reports.
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