We have adopted the definitions used by the Cochrane 2 Evidence-Based Complementary and Alternative Medicine Collaboration: a systematic review is a review of a clearly formulated question, that which uses systematic and explicit methods to identify, select, and critically appraise relevant researches, and to collect and analyze data from the studies included in the review [9] . Then a search strategy for locating systematic reviews on TCM was formulated by using the definitions; search terms included "Chinese medicine", "Chinese herb", "plant preparations", "Chinese medical formula," "meta analysis," "meta-analysis," "meta-analyses," and "systematic review." We performed a comprehensive search on CNKI (China National Knowledge Infrastructure), CBM (Chinese Biomedical Database), VIP (Chongqing VIP periodicals Database), Medline and EMbase databases (January 1, 1999 to the end of 2008) in addition to hand search on Chinese Journal of Evidence-Based Medicine (incept to the end issue of 2008), Chinese Journal of Integrated Traditional and Western Medicine (from the first issue in 1999 to the end issue in 2008), and Journal of Chinese Integrative Medicine (from the first issue in 1999 to the end issue in 2008). Two reviewers screened the titles and abstracts of identified studies independently, disagreement was resolved by discussion. A total of 165 systematic reviews on TCM were included, full detail of evaluations has been reported separately [10] . We used a computer-generated random sample (approximately 25% of the 165 systematic reviews) as a test set for validation.