Traditional Chinese herbal medicines are frequently used to treat premenstrual syndrome (PMS) in China. Until now, their efficacy has not been systematically reviewed.To evaluate the effectiveness and safety of traditional Chinese herbal medicines in the treatment of women with premenstrual syndrome.We searched MEDLINE (January 1950 to December, 2007), EMBASE (January 1980 to December, 2007), Chinese Biomedical Database (CBM) (January 1975 to December, 2007), China National Knowledge Infrastructure (CNKI) (January 1994 to December, 2007), and the VIP Database (January 1989 to December, 2007).Randomised controlled trials (RCTs) studying the efficacy of traditional Chinese herbal medicine(s) for treatment of the premenstrual syndrome were included.Two review authors telephoned the original authors of the RCTs to confirm the randomisation procedure, extracted and analysed data from the trials that met the inclusion criteria.Two RCT considering 549 women were included. One trial which was identified to be of higher methodological quality demonstrated the therapeutic effectiveness of Jingqianping granule. The other study was considered of lower quality due to the inherent risk of various biases in it. Two studies showed statistically significant differences in elimination of symptoms in proliferative phase and premenstrual phase by taking Jingqianping granule than taking Xiaoyaowan (RR 3.50, 95% CI1.74 to 7.06). Women treated by Cipher decoction had a higher rate of recovery than those taking Co-vitamin B6 capsules (RR 48.99, 95% CI 3.06 to 783.99).It is rare in PMS management that efficacy claims are substantiated by clinical trials. One of the identified trials was well designed and reported on the effectiveness of Jingqianping in the treatment of premenstrual syndrome Qiao 2002. However, currently there is insufficient evidence to support the use of chinese herbal medicine for PMS and further, well controlled, trials are needed before any final conclusions could be drawn.