What Is It? 
Health Benefits
Dosage Information
Guidelines for Use
General Interaction
Possible Side Effects
Evidence Based Rating Scale

What Is It?

An Herb native to China, astragalus (Astragalus membranaceous) has been used for more than 2,000 years to balance the vital energy--or qi--which is thought to flow through all beings. A relative of licorice and the pea plant, astragalus appears to give the immune system a boost. Teas, tablets, and other healing formulations are made from the plant's flat, yellowish root. Taken as a tonic, astragalus is believed to build stamina and vitality. It has a reputation for improving overall health by helping the body to fight off viral and bacterial infections responsible for causing colds, the flu, bronchitis, and sinus infections. Polysaccharides (complex sugar molecules) in the root of astragalus contribute to the plant’s immune-enhancing effects.  Astragalus also works as an Antioxidant helping to counteract cell damage caused by unstable oxygen molecules called Free radicals. Many people undergoing cancer chemotherapy or radiation take astragalus to fortify their battered immune systems. Indeed, one of the great appeals of astragalus is its versatility: It can be safely combined with many conventional medical treatments.

Health Benefits

Traditionally, astragalus has been used to treat colds and upper respiratory infections, allergies, asthma, chronic fatigue, and diabetes, and to protect the liver and to heal wounds. Currently, astragalus is being studied for its potential benefit in boosting immune systems compromised by chemotherapy or radiation; and it is also thought to offer antioxidant benefits to people with severe forms of heart disease.

Specifically, astragalus may help to:

Improve immune function. The ability of astragalus to stimulate the body’s natural defense system is a result of several mechanisms acting together to support immune function. Preliminary research in animals has shown astragalus enhances the phagocytic activity (removal of pathogens and cell debris) of monocytes and macrophages, increases interferon production and natural killer cell activity, improves T-cell activity, and potentiates other antiviral mechanisms. Specifically, this research showed astragalus to be effective when used prophylactically against the common cold. (1, 2) In a 1999 astragalus monograph, The American Herbal Pharmacopoeia noted that the preliminary evidence indicates long-term ingestion of astragalus may reduce the risk of catching the common cold. However, the monograph cautioned that doses in excess of 28 grams may suppress immunity. (3) While clinical studies evaluating the use of astragalus are limited, a 2007 review of cold and flu treatments noted botanical treatments such as astragalus may help prevent and treat these conditions. (4)

Treat cancer. The immune-enhancing properties of astragalus seem to be particularly useful in cases in which the immune system has been damaged by chemicals or radiation. A 1988 University of Texas System Cancer Center study of immuno-depressed mice found astragalus reversed T-cell abnormalities caused by radiation. (5) Other preliminary in vitro and animal studies also indicate efficacy in restoring T-cell function suppressed in cancer patients. A 1983 in vitro study evaluating the effect of 10 mcg/ml of astragalus extract on grafts from 19 cancer patients and 15 healthy donors found the extract seemed to induce T-cell restoration in cancer patients. (6) In addition to immune-boosting properties, the monograph says preliminary evidence also indicates astragalus may help to increase survival rates in breast cancer patients who are also undergoing conventional treatment. (3) And preliminary research regarding lung cancer (mostly low-quality studies) suggests taking herbal products containing astragalus may increase the effectiveness of platinum-based chemotherapy for advanced non-small-cell lung cancer. A 2006 meta-analysis of 34 randomized trials of 2,815 patients with non-small-cell lung cancer compared the use of astragalus treatment combined with platinum-based chemotherapy to treatment of chemotherapy alone. Twelve studies reported treatment with astragalus reduced the risk of death in cancer patients after a 12-month follow up, and 30 studies reported improved tumor response in cancer patients. (7)

Combat allergies. Some evidence indicates the anti-inflammatory properties of astragalus may be useful in treating symptoms of allergic rhinitis, the medical name for a common allergic reaction to a variety of airborne particles. The astragalus monograph and preliminary in vitro and animal evidence have shown astragalus potentiates the effects of interferon (which fights viruses), increases antibody levels of IgA and IgG in nasal secretions, and increases interleukin-2 levels (which stimulate the growth of T-cells). (3, 8-9) However, research in this area is limited. More research is needed to confirm efficacy of astragalus in treating allergies.

Treat hepatitis. The anti-inflammatory properties of astragalus may play a role in reducing inflammation of the liver caused by the hepatitis virus. Preliminary evidence indicates astragalus improves liver function as demonstrated by improved levels of serum glutamate pyruvate transaminase (SGPT) levels--enzymes leaked into the blood from hepatic livers. (3) However, a 2001 Cochrane Database Review of three randomized clinical trials involving 307 asymptomatic carriers of hepatitis B virus treated with Chinese medicinal herbs and followed for three months or more after treatment found astragalus did not show any antiviral effect compared to placebo. (10)

Lower blood sugar. Some animal studies indicate astragalus may help to lower blood sugar levels in Type 1 diabetes, an autoimmune disorder in which the body’s immune system mistakenly attacks cells of the pancreas that produce insulin—needed to utilize the blood sugar all cells need for energy. A 2008 Chinese study found the polysaccharides in astragalus seem to both improve cell and humoral-mediated immunity in diabetic mice. (11) Clinical research evaluating the use of astragalus to lower blood sugar in humans is needed to confirm potential efficacy.

Improve heart disease. Some research suggests astragalus causes vasodilatation and increases cardiac output, important to patients with angina, congestive heart failure, and post-myocardial infarction. (3) In animal models of heart failure, astragalus seems to increase myocardial and renal function, possibly due to diuretic and natriuretic (sodium-clearing) effects. (12) In a 2004 Cochrane Database Review of 40 randomized trials evaluating the use of herbal treatments in 3,448 patients with viral myocarditis, astragalus (either as a single herb or in a combination of herbs) showed significant effects on improving arrhythmia, CPK (Creatinine Phosphokinase—enzyme levels that increase with muscle damage), and cardiac function. (13) However, most of the studies reviewed were low-quality, had small sample sizes, and limited trials on individual herbs. More research is needed in this area.


  • Capsule
  • IV
  • Ointment
  • Powder
  • Tablet
  • Tea
  • Tincture

Dosage Information

To ensure effectiveness, select an astragalus product that contains a Standardized Extract of the root, with 0.5% glucosides and 70% polysaccharides. For help with the many Traditional Chinese Medical uses of astragalus, consult a practitioner trained in prescribing the various herbal formulas where astragalus is used as one of the immune system support ingredients.

Guidelines for Use

If taken over long stretches of time, the body can develop a tolerance to an immune-stimulating herb such as astragalus. So, for maximum effect, alternate the use of astragalus with other immune-boosting herbs such as echinacea, cat's claw, and pau d'arco.

Doses from 1 to 25 g per day have been used. Higher doses may suppress the immune system. Recommended doses are as follows:

  • Decoction (strong boiled tea): 3 - 6 g of dried root per 12 oz. water, three times per day
  • Fluid extract (1:1) in 25% ethanol: 2 - 4 mL three times a day
  • Powdered root: 500 - 1,000 mg three or four times per day
  • Powdered extract (solid): 100 to 150 mg of a product standardized to 0.5% 4-hydroxy-3-methoxy isoflavone. Note: this chemical is used only as a manufacturing marker, not as a guarantee of potency or effectiveness.
  • Ointment: 10% astragalus applied to surface of wound. Do not apply to open wound without your doctor's supervision.
  • Tincture (1:5) in 30% ethanol: 3 - 5 mL three times a day

General Interaction

Because of its immune enhancing properties and the lack of studies on its use in complex medical situations, concurrent use of astragalus with immunosuppressive drugs used in transplant patients and in those with auto-immune diseases such as Lupus, should be avoided as it may reduce the efficacy of those drugs.

Possible Side Effects

There are no known side effects.


  • If you take regular medications of any kind or are undergoing cancer treatment, consult your doctor before adding astragalus to your daily supplement regimen.
  • If you are pregnant or breastfeeding, talk to your doctor before taking any herbs or medication.


1. Chang HM, But PPH, eds. Pharmacology and applications of Chinese material medica. Singapore: World Scientific, 1986:1041-6.
2. Zhao KS, Mancini C, Doria G. Enhancement of the immune response in mice by Astragalus membranaceus extracts. Immunopharmacology. 1990;20:225-233.
3. Upton R, ed. Astragalus Root: Analytical, quality control, and therapeutic monograph. Santa Cruz, CA: American Herbal Pharmacopoeia. 1999:1-25.
4. Roxas M, Jurenka J. Colds and influenza: a review of diagnosis and conventional, botanical, and nutritional considerations. Altern Med Rev. 2007 Mar;12(1):25-48.
5. Chu DT, Wong WL, Mavligit GM. Immunotherapy with Chinese medicinal herbs. Immune restoration of local xenogeneic graft-versus-host reaction in cancer patients by fractionated Astragalus membranaceus in vitro. J Clin Lab Immunol. 1988;25:119-23.
6. 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;52:70-3.
7.  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;24:419-30.
8. Qun L, Luo Q, Zhang ZY, et al. Effects of astragalus on IL-2/IL-2R system in patients with maintained hemodialysis. Clin Nephrol. 1999;52:333-4.
9. 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.
10. Liu, McIntosh H, Lin H. Chinese medicinal herbs for asymptomatic carriers of hepatitis B virus infection. Cochrane Database Syst Rev. 2001;(2):CD002231.
11. Li RJ, Qiu SD, Chen HX, Wang LR. [Immunomodulatory effects of Astragalus polysaccharide in diabetic mice]. Zhong Xi Yi Jie He Xue Bao. 2008 Feb;6(2):166-70.
12. Yang YZ, Jin PY, Guo Q, et al. Treatment of experimental Coxsackie B-3 viral myocarditis with Astragalus membranaceus in mice. Chin Med J (Engl). 1990;103:14-8.
13. Liu JP, Yang M, Du XM. Herbal medicines for viral myocarditis. Cochrane Database Syst Rev. 2004;(3):CD003711.

Evidence Based Rating Scale  

The Evidence Based Rating Scale is a tool that helps consumers translate the findings of medical research studies with what our clinical advisors have found to be efficacious in their personal practice. This tool is meant to simplify which supplements and therapies demonstrate promise in the treatment of certain conditions. This scale does not take into account any possible interactions with any medication/ condition/ or therapy which you may be currently undertaking. It is therefore advisable to ask your doctor before starting any new treatment regimen.





















Preliminary in vitro and animal evidence indicates efficacy in reducing inflammatory response. More research is needed in this area.












Preliminary evidence indicates efficacy. More research is needed..






Date Published: 04/18/2005

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