root and rhizome of Cynanchum stauntonil (Decne.) Schltr.ex. level. or
C. glaucescens (Decne.) Hand.-Mazz., family Asclepiadaceae.
Rhizome slender cylindrical, about 16 cm long, 2-3 mm in diameter. Surface
yellowish white; nodes visible, densely covered by trichomatic fibrous
roots; internode 1.5-4.5 cm long. The dried roots twisting to balls. Acrid
and sweet in taste, mild in nature, and attributive to lung channel.
Open the inhibited lung-energy, relieve cough, descend the adverse-rising
energy and eliminate phlegm: For stagnation of lung-energy with productive
cough, wheezing and dyspnea, usually applicable to cough of wind-cold
and phlegm-dampness types.