Roots of e zhu are oval, long oval, conical or fusiform, 2 to 8cm long, 1.5 to 4cm in diameter, and with tip blunt top and obtuse bottom. Surface is from greyish yellow to gray-brown, with raised upper part and rounded or slightly concave fibrous scar or residual fibrous roots. It is heavy, solid, and with grayish brown to blue-brown waxy section. It is lightly scented, and slightly bitter and acrid in flavor. Main chemical constituents are volatile oil, in which major ingredients include curzerenone, epicurzerenone, curzenene, curdione, curcumol, camphor, borneol, etc.