The Cochrane Collaboration is an international organization that aims to prepare and maintain rigorous systematic reviews in order to help people make well-informed decisions about health care [8] . Compared with reviews published in paper-based journals, Cochrane reviews are noted to have greater methodological quality [9] . Ever since 1999 when the first Cochrane review of CHM was published, a sharp increase has been observed in the number of similar reviews. However, no previous studies have systematically assessed the methodological quality of Cochrane reviews of CHM. Therefore, we did this overview of systematic reviews. Our study had two objectives: a) to systematically identify all existing Cochrane reviews of CHM; b) to assess the methodological quality of included reviews.