Astragalus

Scientific names: Astragalus membranaceus, Astragalus membranaceus var. mongholicus.

Common names: Astragalus also is known as huang chi and huang qi.

Efficacy-safety rating:

ÒÒ...Ethno or other evidence of efficacy.

Safety rating:

...No safety concerns despite wide use.

What is Astragalus?

The genus Astragalus is an enormous group of more than 2,000 species distributed worldwide, commonly known as milk vetches. The Chinese species A. membranaceus and the related A. mongholicus are thought to be varieties of the same species. Both are perennial herbs native to the northern provinces of China and are cultivated in China, Korea, and Japan. The dried root is used medicinally. Astragalus roots are sold as long pieces, which have a tough, fibrous skin with a lighter interior. Some products are produced by frying the roots with honey, although the untreated root itself has a sweet, licorice-like taste.

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What is it used for?

Traditional/Ethnobotanical uses

Astragalus root is a very old, well-known drug in traditional Chinese medicine, and currently is official in the Chinese Pharmacopeia. It is used in China principally as a tonic and for treatment of diabetes and nephritis. It is an important component of Fu-Zheng therapy in China, where the goal is to restore immune system function. There is extensive Chinese literature on the drug.

Immunostimulant

The most common use of astragalus root in herbal medicine in the US is as an immunostimulant to counteract the immune suppression associated with cancer therapy. This use is based on limited observations made in laboratory research. Research reveals no animal or clinical data regarding the use of astragalus as an immunostimulant.

HIV

A second use of astragalus root in the US is for HIV infection. A series of reports from China claim that treatment with herbal mixtures including astragalus can aid a small fraction of HIV patients. These reports need to be verified. One small study on the effects of astragalus showed promise and a larger clinical trial might confirm these effects as significant.

Other uses

Astragalus often is recommended for the prevention of the common cold. However, there are no published clinical trials that support this use.

What is the recommended dosage?

There is no recent clinical evidence to guide dosage of astragalus products. However, typical recommendations call for 2 to 6 g of the powdered root daily.

How safe is it?

Contraindications

The root appears to be safe. However, an observation of mutagenicity (to cause mutations) must be explored.

Pregnancy/nursing

Information regarding safety and efficacy in pregnancy and lactation is lacking.

Interactions

Astragalus may have immunostimulating effects. Therefore, astragalus possibly may interfere with the immunosuppressive effects of cyclosporine and the cortisone class of drugs. Avoid taking astragalus at the same time as these, or other immunomodulating, drugs.

Side Effects

No data.

Toxicities

Astragalus extract was mutagenic in the Ames test.

References

  1. Astragalus. Review of Natural Products. factsandcomparisons4.0 [online]. 2005. Available from Wolters Kluwer Health, Inc. Accessed April 16, 2007.

Copyright © 2009 Wolters Kluwer Health

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