Lang Du

Lang Du is the dried root of Euphorbia fischeriana Steud. (Euphorbiaceae) and, in some regional pharmacopoeias, the root of Stellera chamaejasme L. (Thymelaeaceae); both are HIGHLY TOXIC perennial herbs of dry steppe, grassland, and montane slopes in northern and northwestern China, Mongolia, and Siberia. Euphorbia fischeriana forms a stout, fleshy, branched taproot with pale yellow to reddish-brown bark that exudes copious milky white latex when cut; the erect annual stems 20–50 cm tall bear whorls of narrowly oblong leaves and terminal cyathial inflorescences. Stellera chamaejasme has a stout woody rootstock supporting a cushion of erect stems clothed in lance-shaped leaves and topped with dense heads of fragrant pink-and-white flowers. Roots of either species are dug in autumn, washed, and dried; their irritant diterpene esters and lignans make them powerfully purgative and historically used to expel parasites and reduce masses. WARNING: severely toxic, banned or restricted in several jurisdictions; absolutely contraindicated in pregnancy, debility, and routine outpatient use.