Wenjing decoction (herbal medicine) for the treatment of primary dysmenorrhea: a systematic review and meta-analysis

Wenjing decoction is a well-accepted traditional Chinese medicine for the treatment of primary dysmenorrhea in East Asia, but its clinical effectiveness and risk have not been adequately assessed. In this paper, we conducted a systematic review and meta-analysis to evaluate the efficacy of Wenjing decoction for the treatment of primary dysmenorrhea. Eight databases were used in our research: the Cochrane Library, the Web of Science, PubMed, EMBASE, the Chinese Biomedical Literature Database (CBM), the Chinese National Knowledge Infrastructure (CNKI), the Chinese Scientific Journal Database, and the Wan-fang Database. The following search terms were used: (Wenjing decoction OR Wenjing formula OR Wenjing tang) AND (primary dysmenorrhea OR dysmenorrhea OR painful menstruation) AND (randomized controlled trial). No language limitation was used. A total of 18 studies, including 1736 patients, were included in the meta-analysis. Wenjing decoction was shown to be significantly better than nonsteroidal anti-inflammatory drugs for the improvement of primary dysmenorrhea according to the clinical effective rate (RR 1.41, 95% CI 1.24-1.61), the visual analogue scale (MD -1.77, 95% CI -2.69 to -0.84), and the pain scale for dysmenorrhea (MD -1.81, 95% CI -2.41 to -1.22). The results supported the clinical use of Wenjing decoction for the treatment of primary dysmenorrhea. However, the quality of the evidence for this finding was low due to a high risk of bias in the included studies. Therefore, well-designed randomized controlled trials are still needed to further evaluate the efficacy of Wenjing decoction for the treatment of primary dysmenorrhea.