Efficacy and safety of Wuling capsule, a single herbal formula, in Chinese subjects with insomnia: a multicenter, randomized, double-blind, placebo-controlled trial.

ETHNOPHARMACOLOGICAL RELEVANCE: Wuling Capsule is a single herbal formula from mycelia of precious Xylaria nigripes (Kl.) Sacc and its pharmacological function have a tranquilizing effect on the central nervous system. The aim of the study to evaluate the efficacy and safety of Wuling capsule in treatment of insomnia. MATERIALS AND METHODS: We performed a multicenter, randomized, double-blind, placebo-controlled study. The participants received either placebo (n=92) or Wuling capsule (n=94) for 4 weeks and a follow-up period for 2 weeks. RESULTS: Compared between pre-treatment and post-treatment, the global Pittsburgh sleep quality index (PSQI) scores in both Wuling capsule group and placebo group improved significantly (P<0.01). However, there was no significant difference between Wuling capsule group and placebo group (P>0.05). Scores of clinical global impressions scale (CGI-I) at each week in Wuling capsule group was similar to those in placebo group (P>0.05). Compared between pre-treatment and post-treatment, scores of the four components of world health organization on quality of life brief scale (WHOQOL-BREF) in both Wuling capsule group and placebo group improved significantly (P<0.01). However, there were no difference between the two groups (P>0.05). The rate of adverse events was 10.10% in Wuling group, and 6.73% in placebo group (P>0.05). CONCLUSIONS: Wuling capsule can improve insomnia when compared with pre-treatment for 4 weeks and be a well tolerated by all the patients at the 6 weeks of study period. However, there are no significant in the results of the variables tested when compared with placebo control. Further additional rigorous randomized clinical trials are still required.