Bai Qian
StarCynanchum stauntonii (Decne.) Schltr. ex Levl.
Traditionally used for
- Nose & throat
- Cough & breathing
☯ TCM Properties
Descends Qi; Resolves Phlegm; Stops Cough; Calms Wheezing
Traditional Chinese Uses
Bai Qian (cynanchum root, swallowwort root) is a focused Lung herb used primarily for coughs with abundant phlegm, wheezing, and chest congestion. It works by directing Lung Qi downward and breaking up accumulated phlegm, and is notably gentle compared to stronger cough herbs. It appears in many classical cough formulas and is especially helpful when breathing feels tight and phlegm rattles audibly in the throat or chest.
Western Herbalism Properties
Relationships
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Botanical Description
Cynanchum stauntonii (Decne.) Schltr. ex H. Lév. (Apocynaceae, formerly Asclepiadaceae) is a perennial herb native to China and Japan, growing 30-80 cm tall from slender creeping rhizomes, with erect or slightly twining stems, opposite linear-lanceolate leaves, and small yellow-white flowers in axillary cymes. The medicinal Bai Qian is the dried rhizome with its attached roots, harvested in spring or autumn. The rhizome is thin, cylindrical, jointed with prominent nodes, pale yellow externally, with numerous fine wiry roots; it contains C21 steroidal glycosides (cynanchotoxin and related compounds), triterpenes, and alkaloids. In traditional Chinese medicine, Bai Qian is acrid, sweet, and slightly warm, entering the lung channel; it descends rebellious qi, transforms phlegm, and stops cough, used for cough and wheezing with copious phlegm regardless of whether the pattern is hot or cold. It is paired with Qian Hu in classical formulas for phlegm-stagnation cough.
Active Constituents
Glaucogenin C
C21 steroid, 14,15-secopregnane (seco-pregnane) aglyconeOne of the characteristic seco-pregnane aglycones of the rhizome and root, and the chemical signature that separates this drug from the ordinary C21 pregnane glycosides of the rest of the genus. Glaucogenins A, C, D and E have all been described from this species.
Stauntosides (stauntosides UA, UA1 and UA2 among others)
C21 steroidal glycoside, 14,15-secopregnane typeThe main glycoside series of the root. The stauntoside UA group shares an unusual aglycone, stauntogenin G, carrying a 5-alpha to 9-alpha peroxy bridge and a 6,8(14)-diene; the peroxide bridge is chemically distinctive and is the sort of feature that raises questions about stability during storage and decoction that have not been answered.
Stauntogenin G
C21 steroid aglycone, 14,15-secopregnane with 5-alpha:9-alpha-peroxy and 6,8(14)-dieneThe aglycone shared by stauntosides UA, UA1 and UA2, reported for the first time from this species. Its peroxy linkage is unusual among plant steroids.
Acetophenone derivatives
Aromatic ketone (acetophenone) phenolicsA class shared across the genus Cynanchum, more than 440 compounds of which have been characterised in total, and one of the groups usually recovered from Bai Qian alongside the C21 steroids. Contributes to the anti-inflammatory activity attributed to the drug.
Volatile oil of the rhizome and root
Essential oil (mixed terpenoid and aromatic volatiles)The fraction traditionally connected with the expectorant and cough-suppressing action of Bai Qian. Its composition and its contribution relative to the C21 glycosides are not well characterised in the peer-reviewed literature.
⚠ Drug Interactions
Cynanchum glaucescens rhizome and root
The Chinese Pharmacopoeia accepts both Cynanchum stauntonii and Cynanchum glaucescens as Bai Qian, so material of either species can be supplied legitimately under this name. They are separable pharmacognostically: the pith occupies about half the rhizome diameter in Cynanchum stauntonii but only a small fraction in Cynanchum glaucescens, and laticifers and rhizome epidermal secretory cells are present in the powder of the former and absent from the latter. What is missing is any published comparison of their chemistry or their pharmacology, so equivalence is assumed rather than demonstrated.
Clinical note: Not a safety problem, but do not treat this batch as chemically identical to the last one. If a patient responds well to one supply and poorly to another, ask which species was supplied before concluding the herb has failed.
Cynanchum auriculatum root (Bai Shou Wu, Iyeopupiso)
This is the cautionary case for genus-level substitution in Cynanchum. Cynanchum auriculatum and Cynanchum wilfordii are so alike that, in the words of the Korean regulatory toxicologists who studied them, even experts can barely tell them apart by eye, and a 2015 Korean food safety incident found that most of the Cynanchum wilfordii ingredient on the market was actually Cynanchum auriculatum. Cynanchum auriculatum is not approved as a herbal medicine in Korea and remains prohibited there. In GLP sub-chronic rat studies its water extract raised triglycerides and absolute and relative liver weights with hepatic vacuolation; its powder raised alanine and aspartate aminotransferase in males with single-cell hepatic necrosis and multinucleated hepatocytes, and in females increased adrenal weights with adrenal hypertrophy and vacuolation and ovarian vacuolation. The no-observed-adverse-effect level for the powder was 150 mg/kg/day in both sexes.
Clinical note: Bai Qian is not Bai Shou Wu and neither is a synonym of the other, but they travel in the same genus and the same supply chains. Require the botanical name on the certificate of analysis. If a patient on any Cynanchum product develops raised transaminases, stop the herb and investigate species identity as well as the herb itself.
Cynanchum atratum root (Bai Wei) and Cynanchum paniculatum root (Xu Chang Qing)
An ITS2 barcoding study of 87 samples across 17 Cynanchum species, followed by a survey of 64 commercial samples of three commonly used Cynanchum drugs, found that all 11 tested samples of Cynanchi Atrati Radix et Rhizoma (Bai Wei) were adulterants. The names Bai Qian and Bai Wei differ by a single syllable and the drugs are dried root and rhizome of similar appearance. Cynanchum paniculatum is a separate drug again, with its own distinct chemistry dominated by paeonol. The three are not interchangeable in indication or in constituent profile.
Clinical note: Where Bai Qian and Bai Wei are both stocked, keep them physically separated and labelled with Latin names. The barcoding evidence shows that morphological inspection alone is not catching these substitutions at commercial scale, so prefer suppliers who DNA-authenticate.
Two undisclosed adulterants quantified in commercial Cynanchum stauntonii by near-infrared spectroscopy
A chemometric near-infrared method was developed specifically to quantify two adulterants in commercial Cynanchum stauntonii, which establishes that adulteration of this drug is common enough to warrant a dedicated rapid screening method. The published record here is analytical rather than clinical, and no adverse outcome has been attributed to the practice.
Clinical note: Treat this as a potency and reliability concern rather than an acute hazard. Unusually cheap Bai Qian, or material with an atypical proportion of fine fragments, is worth querying with the supplier.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 3–10 g | Daily | — | — | 中国药典 2020 【用法与用量】3～10g。 【性味与归经】辛、苦，微温。归肺经。 — Chinese Pharmacopoeia 2020, quoted verbatim; route and cautions preserved. Replaces a cleared category-filler value. |
Dui Yao — Herb Pairs
The classical two-herb combinations this herb appears in, each with an action neither herb has alone.
One disperses wind-heat and descends qi, the other descends qi and dispels phlegm; together they stop cough with copious phlegm whether or not an exterior pattern remains.
Named pairing — Lü Jingshan, Shi Jinmo Dui Yao
Evidence Tier
Moderate evidence · 3 studiesRecorded studies by study design, strongest design at the top. This is a study-design tier only, not a GRADE rating: it does not weigh risk of bias, consistency or precision.
Systematic review / meta-analysis
0
Randomized controlled trial
0
Other clinical trial
0
Observational / case report
0
In vitro / animal
3
0 verified · 3 unverified
Show 3 studies
- Integrating UPLC-Q-Orbitrap MS with serum pharmacochemistry network and experimental verification to explore the pharmacological mechanisms of Cynanchi stauntonii rhizoma et radix against sepsis-induced acute lung injury
- Comparative sub-chronic toxicity studies in rats of two indistinguishable herbal plants, Cynanchum wilfordii (Maxim.) Hemsley and Cynanchum auriculatum Royle ex Wight
- 14,15-Secopregnane-Type Glycosides with 5α:9α-Peroxy and Δ6,8(14)-diene Linkages from the Roots of Cynanchum stauntonii
Other / unclassified
0
Verified: design read from PubMed for a DOI that resolves to the cited paper Unverified: taken from the study's recorded description
Clinical Studies
Integrating UPLC-Q-Orbitrap MS with serum pharmacochemistry network and experimental verification to explore the pharmacological mechanisms of Cynanchi stauntonii rhizoma et radix against sepsis-induced acute lung injury
The only substantial pharmacology study on this drug in the indexed English literature. Forty-six bioactive components were identified by UPLC-Q-Orbitrap MS, network analysis produced 192 candidate targets against acute lung injury and ten core genes, with PI3K-Akt, apoptosis and p53 pathways predominating, and the predictions were then tested in a lipopolysaccharide-induced acute lung injury model in mice with western blot, immunohistochemistry and TUNEL staining. Protection was attributed to p53-mediated apoptosis and inflammatory pathways. Note that sepsis-induced acute lung injury is not the traditional indication of cough and phlegm, and that this is mouse work.
Comparative sub-chronic toxicity studies in rats of two indistinguishable herbal plants, Cynanchum wilfordii (Maxim.) Hemsley and Cynanchum auriculatum Royle ex Wight
GLP sub-chronic rat toxicity studies of two Cynanchum congeners, included here for the genus-level safety signal rather than for Bai Qian itself. Cynanchum wilfordii water extract showed no adverse effects, with a no-observed-adverse-effect level above 5000 mg/kg/day, while Cynanchum auriculatum water extract raised triglycerides and liver weights with hepatic vacuolation, and its powder raised transaminases with single-cell hepatic necrosis in males and produced adrenal hypertrophy and ovarian vacuolation in females, giving a powder no-observed-adverse-effect level of 150 mg/kg/day for both sexes. Two closely related species, one benign and one hepatotoxic at achievable doses.
14,15-Secopregnane-Type Glycosides with 5α:9α-Peroxy and Δ6,8(14)-diene Linkages from the Roots of Cynanchum stauntonii
Isolation and structure elucidation of three new 14,15-secopregnane glycosides, stauntosides UA, UA1 and UA2, from the roots, sharing a newly reported aglycone named stauntogenin G with 5-alpha:9-alpha-peroxy and 6,8(14)-diene features. Pure chemistry with no bioassay, which is representative of the literature on this herb: the constituents are well described and the pharmacology is not.
Historical Texts
Ming Yi Bie Lu (Miscellaneous Records of Famous Physicians)
Six Dynasties, c. 500 CE, compiled by Tao HongjingBen Cao Gang Mu (Compendium of Materia Medica)
Ming dynasty, 1596, Li ShizhenChinese Pharmacopoeia, current edition
Modern, 21st centuryReferences
- Sutcharitchan C, Wang Ln, Zhang H, Li Xd, Cui Yj, Ji S. Pharmacognostical study of Cynanchum stauntonii and Cynanchum glaucescens, botanical sources of TCM Baiqian . Chinese Herbal Medicines (2018) [DOI]
- Guo M, Ren L, Pang X. Inspecting the True Identity of Herbal Materials from Cynanchum Using ITS2 Barcode . Frontiers in Plant Science (2017) [DOI]
- Han L, Zhou X, Yang M, Zhou L, Deng X, Wei S, Wang W, Wang Z, Qiao X, Bai C. Ethnobotany, Phytochemistry and Pharmacological Effects of Plants in Genus Cynanchum Linn. (Asclepiadaceae) . Molecules (2018) [DOI]
- Zhang M, Wang JS, Luo J, Wei DD, Kong LY. Glaucogenin E, a new C21 steroid from Cynanchum stauntonii . Natural Product Research (2013) [DOI]
- Dong WJ, Ni YN, Kokot S. Quantitative analysis of two adulterants in Cynanchum stauntonii by near-infrared spectroscopy combined with multi-variate calibrations . Chemical Papers (2012) [DOI]
- Yu JQ, Zhao L. Seco-pregnane steroidal glycosides from the roots of Cynanchum stauntonii . Phytochemistry Letters (2016) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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