Astragalus has been used in traditional Chinese medicine for thousands of years. It is called milk-vetch root, or Huang qi in Chinese (Chevallier 1996; Huang 1999; Wagner et al. 1996). Chinese research has shown that astragalus promotes diuresis, lowers blood pressure, and increases endurance (Chevallier 1996). The root is medicinally active and has been used primarily to treat viral infections because of its immunomodulatory properties (Huang 1999). Animal research suggests that the immune-enhancing effects of astragalus may result from stimulation of monocytes and macrophages, T-cell activity, and interferon production (Murray and Pizzorno 1998).

Research in China has shown that astragalus may be effective for both the prevention and treatment of the common cold (Murray and Pizzorno 1998). By stimulating the immune system, astragalus can reduce the symptoms and duration of a cold. This immune-enhancing ability has also been shown to raise white blood cell counts in cases of chronic leukopenia. Astragalus may be particularly effective in restoring immune activity in cases of compromised immune status associated with chemotherapy or radiation treatment. Clinical studies in the U.S. have demonstrated that supplementation with astragalus in cancer patients undergoing chemotherapy or radiation speeds recovery and extends life expectancy (Chevallier 1996; Upton 1999).

Astragalus may also be useful for other immune deficiency disorders. Specifically, researchers have investigated whether astragalus enhances immune function in AIDS patients in Tanzania (Huang 1999). Some of the HIV-positive patients who were treated with the herb converted to seronegative status and showed clinical improvement. While these results appear intriguing, questions regarding study design remain.

Recent research has focused on whether astragalus may be of benefit for severe forms of heart disease. In one study in China, 43 patients with acute myocardial infarction were observed for 4 weeks; those who were treated with astragalus showed strengthened left ventricular function (Chen et al. 1995). In addition, astragalus exhibited antioxidant benefits by reducing oxygen free radicals; this effect is thought to be a possible mechanism for the cardiotonic action of this herb. In another study involving 92 patients with ischemic heart disease that was also conducted in China, astragalus significantly relieved symptoms of angina pectoris (Li et al. 1995). These findings suggested a higher success rate with astragalus treatment compared to standard drug therapy.

In China, astragalus has also been used both orally and intravenously for treating chronic hepatitis. Elevated serum levels of SGPT returned to normal and symptoms subsided during the 1 to 2 months of treatment (Upton 1999).

Additional in vitro researchhas suggested that astragalus increases sperm motility (Hong et al. 1992). While the clinical relevance of this finding is unknown at this time, these effects may warrant further investigation.

Astragalus is an herbaceous perennial plant that grows to 16 inches tall (Chevallier 1996). It has hairy stems with leaves made up of 12 to 18 pairs of leaflets. It is native to the northern and eastern parts of China, as well as Mongolia. The root is usually harvested from 4-year-old plants.

Dried root (Chevallier 1996; Huang 1999)

Coumarin and flavonoid derivatives such as rhamnocitrin, calycosin, formononetin, and kumatakenin; saponins; asparagines; astragalosides; sterols; polysaccharide; and betaine (Chevallier 1996; Huang 1999; Luo et al. 1995; Murray and Pizzorno 1998; Upton 1999; Wang and Han 1992)

Actions: immunomodulatory, antiviral, antioxidant, antitumor, diuretic, vasodilative, hepatoprotective, cardiotonic (Castillo et al. 1993; Chen et al. 1995; Kurashige et al. 1999; Luo et al. 1995; Ma et al. 1998; Peng et al. 1995; Upton 1999)

Traditional Uses: cold, influenza, wound healing, chronic fatigue, persistent infection, shortness of breath, diabetes, night sweats, multiple allergies, glandular fever, fatigue or lack of appetite in chemotherapy patients, stomach ulcers, uterine bleeding, prolapsed uterus, anemia (Chen et al. 1995; Chevallier 1996; Chu et al. 1988a; Hong et al. 1992; Huang 1999; Ma et al. 1998; Miller and Murray 1998; Murray and Pizzorno 1998; Upton 1999)

Clinical Applications: Astragalus is primarily used clinically for the prevention and treatment of general digestive disorders such as diarrhea, gas, and bloating. It may also be of value for patients with chronic phlegm production, particularly if symptoms flair with exposure to damp weather.

The saponins and polysaccharide components have been isolated as the active constituents of astragalus (Huang 1999; Murray and Pizzorno 1998). The saponins in astragalus exhibit immunomodulating activity (Huang 1999). They significantly reduced the titer of nicotinic acetylcholine receptor antibodies in experiments with blood samples from patients with myasthenia gravis. Based on this finding, researchers concluded that the ability of astragalus to lower nicotinic acetylcholine receptor antibodies might be the underlying mechanism for its effects in the treatment of autoimmune disorders. More research is needed given that astragalus is generally considered an immune-stimulating herb.

The polysaccharide component in astragalus has exhibited antitumor properties and induces interferon to promote antiviral activity (Huang 1999). Animal studies have revealed that the polysaccharide may also impart protective antioxidant benefits (Wang and Han 1992).

Chinese researchers have used the astragaloside component to treat heart disease in 19 patients with congestive heart failure (Luo et al. 1995). After 2 weeks of treatment with astragaloside injections, the results suggested that this component relieved symptoms of chest distress and increased exercise capabilities. Astragaloside may exert a positive inotropic effect with the ability to improve both left ventricular function and cardiac output in patients with congestive heart failure.

Decoction: prepare with 3 to 6 g of dried root per 12 oz. water (Upton 1999)

Tincture (1:5, 30% ethanol): use 3 to 5 ml tid

Fluidextract (1:1, 25% ethanol): use 2 to 4 ml tid

Powdered extract (solid): 100 to 150 mg of a product standardized to 0.5% 4-hydroxy-3-methoxy isoflavone is suggested. Note: This chemical is only used as a manufacturing marker, not as a guarantee of potency or efficacy.

Ointment: 10% astragalus applied to surface of wound (Huang 1999)

No known side effects. Astragalus can be used safely as acute or chronic therapy in debilitated individuals who may not otherwise seem to be able to tolerate many supplements.

Given the value of astragalus for immune stimulation, it may be wise to avoid use in cases of autoimmune disorders (Upton 1999).

While there are no specific restrictions against usage during pregnancy or breast-feeding, in general, it is better to refrain from using any medications during this time unless absolutely necessary.

Because astragalus has antiviral properties, it may potentiate the effects of medications such as acyclovir and interferon (Upton 1999). Clinical studies in this area may be warranted.

A laboratory study investigated the immunomodulatory effects of a partially purified fraction of astragalus (5.55 mg IV) following exposure to cyclophosphamide (100 mg/kg IV) in rats (Chu et al. 1988b). Astragalus reversed the immunosuppressive effects of cyclophosphamide, as demonstrated by increased rejection of grafted human mononuclear cells. However, results obtained from a study in rats that used astragalus (240 mg crude extract) with cyclophosphamide (75 mg/kg IV) found that the herb did not prevent cyclophosphamide-induced myelosuppression (Khoo and Ang 1995).

According to the American Herbal Products Association (AHPA), astragalus has a class 1 safety rating (McGuffin et al. 1997). This means that consumption of this herb is considered to be safe when it is used appropriately.

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Chen LX, Liao JZ, Guo WQ. Effects of Astragalus membranaceus on left ventricular function and oxygen free radical in acute myocardial infarction patients and mechanism of its cardiotonic action [in Chinese]. Chung Kuo Chung Hsi I Chieh Ho Tsa Chih. 1995;15(3):141-143.

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Chu DT, Wong WL, Mavligit GM. Immunotherapy with Chinese medicinal herbs. I. Immune restoration of local xenogeneic graft-versus-host reaction in cancer patients by fractionated Astragalus membranaceus in vitro. J Clin Lab Immunol. 1988a;25(3):119-123.

Chu DT, Wong WL, Mavligit GM. Immunotherapy with Chinese medicinal herbs. II. Reversal of cyclophosphamide-induced immune suppression by administration of fractionated Astragalus membranaceus in vivo. J Clin Lab Immunol. 1988b;25(3):125-129.

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Khoo KS, Ang PT. Extract of Astragalus membranaceus and Ligustrum lucidum does not prevent cyclophosphamide-induced myelosuppression. Singapore Med J. 1995;36:387-390.

Kurashige A, Akuzawa Y, Endo F. Effects of astragali radix extract on carcinogenesis, cytokine production, and cytotoxicity in mice treated with a carcinogen, N-butyl-Ną-butanolnitrosoamine. Cancer Invest. 1999;17(1):30-35.

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Ma J, Peng A, Lin S. Mechanisms of the therapeutic effect of Astragalus membranaceus on sodium and water retention in experimental heart failure. Chin Med J (Engl). 1998;111(1):17-23.

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