Bai Qian (Glaucescent Swallowwort Rhizome)

Name

Bai Qian (Rhizoma Cynanchi Stauntonii), from Ming Yi Bie Lu (Miscellaneous Records of Famous Physicians)

Source and quality

The dry root tuber or root of the perennial herbaceous plants Cynanchum stauntonii (Decne.) Schltr. ex Levl. or C. glaucescens (Decne.) Hand.-Mazz. of the family Metaplexis. It is produced in Zhejiang, Anhui and Jiangsu provinces, and collected in autumn.

It has a slight odor and a slightly sweet taste. The best grade is thick. It is used raw or processed with honey.

Nature and action

Pungent, bitter and slightly warm. It enters the lung meridian.

It directs qi downward and eliminates phlegm, relieves cough and relieves dyspnea.

Indications

Cough with profuse phlegm, and dyspnea

This herb is slightly warm in nature and is neither dry nor drastic. It excels at directing lung qi downward and eliminating phlegm, which makes it a commonly used herb for treating cough and dyspnea: once qi is directed downward and phlegm resolved, cough, dyspnea and fullness in the chest disappear.

It may be used for cough and dyspnea arising from external or internal invasion, of cold or heat, and of new or long-standing pattern, and especially for cold-phlegm obstruction of the lung with lung qi failing to descend.

• For cough and dyspnea due to cold-phlegm, it is usually combined with herbs that warm and resolve cold-phlegm, such as Bai Jie Zi, Ban Xia and Su Zi.
• For cough with unsmooth expectoration due to invasion by wind-cold, it is combined with herbs that ventilate the lung and release the exterior, such as Jing Jie and Jie Geng in Zhisou San from Yi Xue Xin Wu.
• For cough and dyspnea due to accumulation of pathogenic heat in the lung, it is combined with herbs that clear and purge lung heat, such as Sang Bai Pi and Ting Li Zi in Bai Qian Wan from Sheng Ji Zong Lu.
• For impairment of lung qi and yin due to long-standing illness, it is combined with herbs that replenish qi and moisten the lung, such as Huang Qi and Bei Sha Shen.

Dosage and administration

Decoct 3~10 g, or use it in pills and powder. Bai Qian processed with honey is mild in nature and is used mainly for lung yin deficiency with reversed flow of qi and a non-productive cough.

Cautions

This herb stimulates the stomach mucosa, so use it with caution in anyone with stomach disease or a tendency to bleeding. Use with caution in cough and dyspnea due to lung deficiency.