How does yarrow work?

While it may not have the same degree of mechanistic evidence behind it as some other herbs, the active components found in yarrow may provide some support for its traditional uses.^[1] Yarrow is known to contain the compounds apigenin; luteolin; camphor; borneol; centaureidin; quercetin; 5-hydroxy-3’,4’,6,7-tetramethoxyflavone; thujone; dicaffeoylquinic acid; 1,8-cineole; and chlorogenic acid (among many others).^[1][2][3] The antioxidant, anti-inflammatory, antimicrobial, antispasmodic, estrogenic, pain-reducing, hepatoprotective, and vasodilatory effects of the individual constituents of yarrow are already known, and may explain some of the herb’s purported effects.^[1][2][3] Further mechanistic studies are needed to further understand the biological activity and bioavailability of these components when taken together in the whole herb or in an herbal extraction.