Chinese herbal medicine for headache: A systematic review and meta-analysis of high-quality randomized controlled trials

Chinese herbal medicines (CHMs) are widely used to relieve headache in Asia. However, it is uncertain whether there is robust evidence on the effects of CHMs for headache.To assess the effectiveness and safety of CHMs for headache using systematic review of high-quality randomized controlled trials (RCTs).Electronic search was conducted on six databases from inception to January 2018. We included the RCTs that met the requirement of at least 4 out of the 7 domains according to the Cochrane risk of bias tool.Thirty RCTs with 3447 subjects were ultimately included for analysis and all trials were conducted in Asia. Meta-analysis showed that CHMs monotherapy were superior to placebo in reducing headache frequency [SMD -0.48 (95% CI -0.76, -0.20); p < 0.01], headache days [SMD -0.29 (95% CI -0.45, -0.13); p < 0.01], headache duration[SMD -0.58 (95% CI -0.81, -0.36); p < 0.01], headache intensity [SMD -0.42 (95% CI -0.62, -0.23); p < 0.01] and analgesic consumption [SMD -0.36 (95% CI -0.52, -0.21); p < 0.01] and improving clinical efficacy rate (p < 0.01). Similarly, CHMs monotherapy were superior to western conventional medicines (WCMs) in headache frequency [SMD -0.57 (95% CI -0.84, -0.29); p < 0.01], headache days (p < 0.01), analgesic consumption [SMD -1.63 (95% CI -1.98, -1.28); p < 0.01], headache intensity [SMD -0.81 (95% CI -1.06, -0.57); p < 0.01], and clinical efficacy rate [RR 1.24 (95% CI 1.18, 1.31); p < 0.01], except reducing headache duration (p > 0.05). CHMs adjunct therapy can improve clinical efficacy rate compared with WCMs alone [RR 1.15 (95% CI 1.09, 1.22); p < 0.01]. Meanwhile, CHMs had fewer adverse events than that of controls.The findings supported, at least to an extent, the use of CHM for headache patients; however, we should treat the results cautiously because the clinical heterogeneity.