Cang zhu, also known as black atractylodes rhizome or Rhizoma Atractylodes, is a Chinese herbal medicine. It is the dried rhizome of Atractylodes lancea (Thunb.) DC., Atractylodes chinensis (DC.) Koidz, or certain other local species including Atractylodes japonica Koidz. Many compounds isolated from a hexane extract of Atractylodes lancea included atractylochromene, a potent inhibitor of 5-lipoxygenase (IC50 3.3 micromolar) and cyclooxygenase (IC50 0.6 micromolar); 2-[(2E)-3,7-dimethyl-2,6-octadienyl]-6-methyl-2,5-cyclohexadiene-1,4-dione, a selective inhibitor of lipoxygenase (IC50 0.2 micromolar); atractylon and osthol, weak inhibitors of lipoxygenase, and atractylenolides I, atractylenolides II, and atractylenolides III. The rhizome is dug up in the spring. After cleaning, it can be sliced and stir baked to a yellow brown color. A. lancea is grown mainly in Hubei and Jiangsu. A. chinensis and A. japonica are grown in Jilin, Liaoning, Shandong, Inner Mongolia, and Korea.