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Botanical Name: Astragalus membranaceus (Fisch.) Bunge.
Pharmacopoeial Name:Radix astragali.
Common Names:Astragalus, milk vetch root, Huang-Qi.

Summary Table
herb description



Related Species

Astragalus membranaceus var. mongholicus (Bunge).

Habitat and Cultivation

Perennial member of the legume family, native to Northern China, Mongolia, and Siberia and now under organic cultivation in the United States. The genus contains more than 400 species. Wild “locoweeds” (various Astragalus spp.) are a common livestock forage food. Gum tragacanth is derived from a related species, A. gummifer .

Parts Used

Radix (root).

Common Forms

  • Dried Sliced Root:   Often soaked, then pressed or flattened; variant preparation may be honey-roasted in Chinese medicine.

  • Powdered Root:   For decoction, liquid extracts and tablets.

  • Tincture and Fluid Extracts:   60% to 70% ethanol; usually include a water-extraction phase for polysaccharides, then preserved in ethanol.

  • Standardized Extracts:   Several preparations are available. There is no consensus on marker compounds for standardization at this time; individual manufacturers’ preparations may vary.

herb in clinical practice


Astragalus has been used for more than 2000 years in Chinese medicine and is one of several important materia medica imports into Western botanical medicine. The herb is primarily used in Western herbalism as an immunomodulating agent and for cardiovascular disease. Interest in the herb as an adjunct to chemotherapy in oncological settings is increasing, but a recent Cochrane review found limited evidence of value for astragalus decoctions in improving adverse effects of chemotherapy in colorectal cancer patients. 1 Another, more recent meta-analysis reviewed trials in which astragalus was combined with platinum agents in non–small cell lung cancer; evidence showed that the combination may provide increased effectiveness in terms of tumor response, reduced toxicity of the chemotherapy, survival time, or performance status. 2

Most available scientific literature is published in Chinese and has not been directly accessed for this survey. Much of the experimental data on astragalus are based on isolated polysaccharide fractions, either in vitro or by intraperitoneal administration in vivo. Extrapolation from this data to human oral consumption of powdered crude herb or liquid extracts may not be appropriate, particularly with regard to dosage. Chinese clinical trials usually use the herb in combination formulae with other herbs, such as ginseng, dang gui, poria, and rhemannia, because this is the typical manner of clinical administration. The available data have been used to discuss the interactions later.

Astragalus, as with other East Asian herbs incorporated into the Western materia medica relatively recently, is not monographed by the German Commission E, European Scientific Cooperative on Phytotherapy (ESCOP), or World Health Organization (WHO). Astragalus does have an American Herbal Pharmacopoeia monograph, 3 and the literature has been reviewed by McKenna et al. 4 and Wagner et al. 5 Bensky et al. 6 provide an authoritative review, and Chen and Chen 7 relate traditional Chinese uses to conventional pharmacology.

Historical/Ethnomedicine Precedent

Chinese uses include spleen (Pi) qi tonification, lung (Fei) qi tonification, and “securing the exterior”; promoting pus discharge and growth of new tissue and providing immune support. These features may contribute to a number of different biomedical pathological conditions. Astragalus is traditionally used in Chinese medicine in combination formulae for a wide range of conditions, from the common cold to chronic renal failure. 7

Known or Potential Therapeutic Uses

Cardioprotection (anti-ischemic, fibrinolytic, antioxidant); immunostimulation (reversal of leukopenia, myelosuppression); general prophylaxis of infection, stress, hypertension, certain viral infections (coxsackieviruses B2 and B3, parainfluenza type 1, viral myocarditis, Japanese endocarditis, HSV-1), nephritis, nephropathy, oxidative stress psoriasis, prostatic hypertrophy, and Takayasu arteritis.

Key Constituents

Polysaccharides (astragalans or astragologlucans); triterpene saponins (astragolides I-VII); isoflavones and other flavonoids; amino acids, minerals, essential oils, and phytosterols.

Therapeutic Dosing Range

  • Dried Root:   10 to 15 g daily; by decoction, maximum 120 g in Chinese medicine.

  • Hydroethanolic Extracts:   10 to 20 mL daily (based on 1:1 equivalent).

interactions review

Strategic Considerations

Astragalus is used in Western botanical medicine as a tonic, adaptogenic, immunomodulating herb with negligible toxicity. It is myeloprotective, with added cardioprotective, hepatoprotective, and antioxidant properties, which make it a potentially useful adjunct in contexts involving immunosuppression, whether through disease processes, such as human immunodeficiency virus (HIV) and chronic fatigue immune dysfunction syndrome (CFIDS), or drug induced, such as myelosuppressive chemotherapies for the treatment of malignancies and immunosuppression in allograft patients. Recent research on the cardiac properties of the herb may help expand the Western use of astragalus beyond the narrow confines of “immunomodulation.” 9,10

Astragalus use with pharmaceutical immunosuppression (i.e., allograft patients) may be theoretically problematic, but there are no reports of adverse interactions arising from its use in this context. Combination with immunosuppressants may be regarded as contraindicated in practice. Several interactions described later are based on pharmacodynamic effects of the herb on immune parameters. These interactions are not generally supported by published clinical trials; however, strategic coadministration of the herb in some of the therapeutic contexts described is anecdotally established practice among some practitioners of botanical and integrative medicine.

Effects on Drug Metabolism and Bioavailability

There is currently no evidence of interactions resulting from the effects of astragalus on drug-metabolizing systems. A rodent study examining the hepatoprotective effects of astragalus saponins against acetaminophen-induced toxicity found a significant increase in hepatic cytochrome P450 (CYP) levels after astragalus administration. 11 Although studies are lacking, clinically significant pharmacokinetic interactions have not been reported to date.

herb-drug interactions
Acyclovir and Related Purine Nucleoside Analog Antivirals
Aldesleukin (IL-2)
Cyclophosphamide and Related Myelosuppressive Chemotherapy, Especially Alkylating Agents
  • Evidence: Cyclophosphamide (Cytoxan, Endoxana, Neosar, Procytox).
  • Extrapolated, based on similar properties: Busulfan (Myleran), carboplatin (Paraplatin), chlorambucil (Leukeran), cisplatin ( cis-diaminedichloroplatinum, CDDP; Platinol, Platinol-AQ), dacarbazine (DIC, DTIC, DTIC-Dome, imidazole carboxamide), ifosfamide (Ifex, Mitoxana), mechlorethamine (Mustargen, nitrogen mustard), melphalan (Alkeran), oxaliplatin (Eloxatin), phenylalanine mustard (Melphalan), pipobroman (Vercyte), streptozocin (Zanosar), temozolomide (Temodar), thiotepa (Thioplex), uracil mustard (uramustine).
Prevention or Reduction of Drug Adverse Effect
Beneficial or Supportive Interaction, with Professional Management
/ Bimodal or Variable Interaction, with Professional Management

Probability: 2. Probable
Evidence Base: Emerging

Effect and Mechanism of Action

Astragalus reduces the effects of cyclophosphamide-induced suppression of cell-mediated immunity, increasing white blood cell (WBC) counts in chemotherapy-induced leukopenia and neutropenia, and is lymphoproliferative at splenic and bone marrow levels. In the context of cyclophosphamide treatment of nonmalignant disease, the interaction is theoretically adverse, although properly speaking, this is a “contraindicated” combination.


Several studies using cells from human cancer and healthy control patients in graft-versus-host (GVH) reaction models suggest that astragalus polysaccharide extracts promote cell-mediated immunity and reverse cyclophosphamide-induced immunosuppression. 13,17,18 Water extracts increase phagocytosis in carbon clearance tests, stimulate splenic lymphocyte proliferation, and increase tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) production by macrophages. 19 Proliferative effects on bone marrow stem cells and peripheral WBCs was observed after intraperitoneal (IP) administration of astragalus in mice. 20 Rodent macrophages were activated by astragalus polysaccharide in vitro, partly through nuclear factor kappa B (NF-κB) activation. 21 Clinical trials with intravenous (IV) astragalus polysaccharide coadministered with chemotherapy have been reported in the Chinese literature with positive results on outcome, versus chemotherapy alone, in terms of survival as well as quality-of-life measures. 22,23

Clinical Implications and Adaptations

The astragalus-cyclophosphamide interaction has been classified as adverse by some authorities, presumably in the context of cyclophosphamide used in autoimmune disease treatment rather than cancer therapy. 24 Astragalus extracts may be incorporated into integrative protocols designed to support patients undergoing any myelosuppressive chemotherapies. Combination formulae are typically used in these applications, and experimental evidence indicates that such combinations may be more efficacious than the single herb against cyclophosphamide immunotoxicity. 25 Lymphopenia also occurs frequently in cancer patients, before, during, and after chemotherapeutic interventions, and correlates with decreased immunocompetence. To the degree that astragalus and other botanicals can support lymphocyte counts in such patients, these agents may be of clinical benefit, although controlled trials are required to demonstrate efficacy.

Interferon Alpha (IFN-α)
Thrombolytic Agents
theoretical, speculative, and preliminary interactions research, including overstated interactions claims
Aminoglycoside Antibiotics
Oral Hypoglycemic Agents and Insulin
  • 1.Taixiang W, Munro AJ, Guanjian L. Chinese medical herbs for chemotherapy side effects in colorectal cancer patients. Cochrane Database Syst Rev 2005:CD004540.View Abstract
  • 2.McCulloch M, See C, Shu XJ et al. Astragalus-based Chinese herbs and platinum-based chemotherapy for advanced non-small-cell lung cancer: meta-analysis of randomized trials. J Clin Oncol 2006;24:419-430.View Abstract
  • 3.Upton R. Astragalus root. American Herbal Pharmacopoeia. Santa Cruz, CA; 1999.
  • 4.McKenna DJ, Jones K, Hughes K. Astragalus. Botanical Medicines. 2nd ed. New York: Haworth Press; 2002.
  • 5.Wagner H, Bauer R, Peigen X, Jianming C. Radix Astragali [Huang Qi]. Chinese Drug Monographs and Analysis. Bayer Wald:Verlag für Ganzheitliche Medizin Dr Eric Wühr GmbH; 1997;1(8):18.
  • 6.Bensky D, Clavey S, Stogër E, Gamble A. Ren Shen. Chinese Herbal Medicine: Materia Medica. 3rd ed. Seattle: Eastland Press; 2004:710-714.
  • 7.Chen J, Chen T. Huang Qi (Radix Astragali). Chinese Medical Herbology and Pharmacology. City of Industry, CA: Art of Medicine Press Inc; 2004:847-853.
  • 8.Bruneton J. Toxic Plants Dangerous to Humans and Animals. Hatton CK, Translator. 1st ed. Andover, UK: Intercept Ltd; 1999.
  • 9.Zhang W-D, Chen H, Zhang C et al. Astragaloside IV from Astragalus membranaceus shows cardioprotection during myocardial ischemia in vivo and in vitro. Planta Med 2006;72:4-8.
  • 10.Shen P, Liu MH, Ng TY et al. Differential effects of isoflavones, from Astragalus membranaceus and Pueraria thomsonii, on the activation of PPARalpha, PPARgamma, and adipocyte differentiation in vitro. J Nutr 2006;136:899-905.View Abstract
  • 11.Zhang YD, Shen JP, Zhu SH et al. [Effects of astragalus (ASI, SK) on experimental liver injury]. Yao Xue Xue Bao 1992;27:401-406.View Abstract
  • 12.Zuo L, Dong X, Sun X. The curative effects of Astragalus membranaceous Bunge (A6) in combination with acyclovir on mice infected with HSV-1. Virol Sin 1995.
  • 13.Chu DT, Lepe-Zuniga J, Wong WL et al. Fractionated extract of Astragalus membranaceus, a Chinese medicinal herb, potentiates LAK cell cytotoxicity generated by a low dose of recombinant interleukin-2. J Clin Lab Immunol 1988;26:183-187.View Abstract
  • 14.Chu D, Sun Y, Lin J et al. [F3, a fractionated extract of Astragalus membranaceus, potentiates lymphokine-activated killer cell cytotoxicity generated by low-dose recombinant interleukin-2]. Zhong Xi Yi Jie He Za Zhi 1990;10:34-36, 35.View Abstract
  • 15.Chu DT, Lin JR, Wong W. [The in vitro potentiation of LAK cell cytotoxicity in cancer and aids patients induced by F3, a fractionated extract of Astragalus membranaceus]. Zhonghua Zhong Liu Za Zhi 1994;16:167-171.View Abstract
  • 16.Wang Y, Qian XJ, Hadley HR, Lau BH. Phytochemicals potentiate interleukin-2 generated lymphokine-activated killer cell cytotoxicity against murine renal cell carcinoma. Mol Biother 1992;4:143-146.View Abstract
  • 17.Sun Y, Hersh EM, Talpaz M et al. Immune restoration and/or augmentation of local graft versus host reaction by traditional Chinese medicinal herbs. Cancer 1983;52:70-73.View Abstract
  • 18.Wang DC. [Influence of Astragalus membranaceus (AM) polysaccharide FB on immunologic function of human periphery blood lymphocyte]. Zhonghua Zhong Liu Za Zhi 1989;11:180-183.View Abstract
  • 19.Yoshida Y, Wang MQ, Liu JN et al. Immunomodulating activity of Chinese medicinal herbs and Oldenlandia diffusa in particular. Int J Immunopharmacol 1997;19:359-370.View Abstract
  • 20.Rou M, Renfu X. The effect of Radix Astragali on mouse marrow hemopoiesis. J Tradit Chin Med 1983;3(3):199-204.
  • 21.Lee KY, Jeon YJ. Macrophage activation by polysaccharide isolated from Astragalus membranaceus. Int Immunopharmacol 2005;5:1225-1233.View Abstract
  • 22.Duan P, Wang Z-m. [Clinical study on effect of Astragalus in efficacy enhancing and toxicity reducing of chemotherapy in patients of malignant tumor]. Zhongguo Zhong Xi Yi Jie He Za Zhi 2002;22:515-517.View Abstract
  • 23.Zou Y-h, Liu X-m. [Effect of astragalus injection combined with chemotherapy on quality of life in patients with advanced non–small cell lung cancer]. Zhongguo Zhong Xi Yi Jie He Za Zhi 2003;23:733-735.View Abstract
  • 24.Mills S, Bone K. The Essential Guide to Herbal Safety. St Louis: Churchill Livingstone; 2005.
  • 25.Wei X, Zhang J, Li J, Chen S. Astragalus mongholicus and Polygonum multiflorum’s protective function against cyclophosphamide inhibitory effect on thymus. Am J Chin Med 2004;32:669-680.
  • 26.Zhang L, Liu Y, Yu Z. [Study on the anti–herpes simplex virus activity of a suppository or ointment form of Astragalus membranaceus combined with interferon alpha 2b in human diploid cell culture]. Zhonghua Shi Yan He Lin Chuang Bing Du Xue Za Zhi 1998;12:269-271.View Abstract
  • 27.Hou YD, Ma GL, Wu SH et al. Effect of Radix Astragali seu Hedysari on the interferon system. Chin Med J (Engl) 1981;94:35-40.View Abstract
  • 28.Zhang WJ, Wojta J, Binder BR. Regulation of the fibrinolytic potential of cultured human umbilical vein endothelial cells: astragaloside IV downregulates plasminogen activator inhibitor-1 and upregulates tissue-type plasminogen activator expression. J Vasc Res 1997;34:273-280.View Abstract
  • 29.Meade TW, Ruddock V, Stirling Y et al. Fibrinolytic activity, clotting factors, and long-term incidence of ischaemic heart disease in the Northwick Park Heart Study. Lancet 1993;342:1076-1079.View Abstract
  • 30.Hamsten A, de Faire U, Walldius G et al. Plasminogen activator inhibitor in plasma: risk factor for recurrent myocardial infarction. Lancet 1987;2:3-9.View Abstract
  • 31.Thogersen AM, Jansson JH, Boman K et al. High plasminogen activator inhibitor and tissue plasminogen activator levels in plasma precede a first acute myocardial infarction in both men and women: evidence for the fibrinolytic system as an independent primary risk factor. Circulation 1998;98:2241-2247.View Abstract
  • 32.Xuan W, Dong M. Effects of compound injection of Pyrola rotundifolia L and Astragalus membranaceus Bge on experimental guinea pigs’ gentamicin ototoxicity. Ann Otol Rhinol Laryngol 1995;104:374-380.View Abstract
  • 33.Wu Y, Ou-Yang JP, Wu K et al. Hypoglycemic effect of Astragalus polysaccharide and its effect on PTP1B. Acta Pharmacol Sin 2005;26:345-352.
  • 34.Li C, Cao L, Zeng Q. Astragalus prevents diabetic rats from developing cardiomyopathy by downregulating angiotensin II type 2 receptors’ expression. J Huazhong Univ Sci Technol Med Sci 2004;24:379-384.