Qian Cao Gen

Qian Cao Gen is the dried root of Rubia cordifolia L. (Rubiaceae), commonly called Indian or Asian madder, a perennial climbing or scrambling herb whose slender four-angled stems bear minute downward-pointing prickles enabling them to clamber 1.5-3 m across surrounding vegetation. The leaves are arranged in whorls of typically four, ovate-cordate, 2-9 cm long, with three to five prominent palmate veins and rough margins. Small, pale yellow, five-lobed flowers in lax terminal and axillary cymes give rise to paired, globose, fleshy black drupes 4-6 mm across. The slender, cylindrical, reddish-brown roots, often branched and 10-30 cm long, contain anthraquinone pigments (alizarin, purpurin) that yield the classical red dye. In TCM the root cools blood, stops bleeding, invigorates blood, and dispels stasis. The closely related European Rubia tinctorum was an important Western dyeplant and folk medicine.