Tatarian aster

A cough of any age that produces thick phlegm only with effort, whether the patient is hot or cold, where it is paired with kuan dong hua

The cough that will not leave after a cold, tickling and phlegmy, with no strong heat or cold signs, the picture of Zhi Sou San

Chronic weak cough with occasional blood streaks in an older patient, using the honey-fried root with bai he and mai men dong

Overview. Zi wan is the dried root and rhizome of the Tatarian aster, a tall perennial with lilac daisy flowers native to grasslands and forest edges across northern China, Mongolia, Siberia, Korea and Japan and widely cultivated in Hebei and Anhui. The fine, fibrous purplish roots are gathered in spring or autumn, plaited into braids and dried, and are used raw or honey-fried. In Chinese medicine it is one of the gentlest and most widely used cough herbs, valued because it neither dries nor cools, and so can be fitted to almost any cough with the right partners.

Clinical Notes. Zi wan is the practitioner's all-purpose cough herb. Its classical partner is kuan dong hua, and the pair appear together in Zhi Sou San (with bai bu, jie geng, bai qian, jing jie, chen pi and gan cao) for the lingering cough after a cold, and in She Gan Ma Huang Tang for cold wheezing with throat rattling.

Chinese Medicine Profile. Temperature: slightly warm. Taste: bitter, acrid, sweet. Channels: Lung. Actions: Moistens the Lung and directs qi downward; Dissolves phlegm and stops cough; Gently unblocks the Lung to relieve wheezing and, by extension, urinary retention.