Evidence Level
Preliminary
Dong quai occupies an unusual position in herbal medicine — it is one of the most widely used herbs in TCM but has limited Western clinical evidence when used alone. Hirata et al. (1997) conducted the only rigorous Western RCT, studying 71 postmenopausal women given dong quai or placebo for 24 weeks. The study found no significant difference in vasomotor symptoms, endometrial thickness, or vaginal maturation between groups. Critics note this study tested dong quai as monotherapy, which contradicts traditional TCM practice where it is always combined with other herbs. Traditional formulas like Si Wu Tang have some clinical evidence from Chinese-language trials but lack the methodological rigor of Western RCTs.