Astragalus membranaceous – Pea Family
by Greg Tilford c.2010
Appearance: A typical member of the pea family, astragalus has pinnately-divided leaves, small pea-like flowers and seed pods, and a sprawling, vine-like stature which brings to mind any of the hundreds of wild vetches that inhabit much of the globe. Astragalus membranaceous, the species of commerce, may grow as tall as six feet, which gives it an appearance that is similar to licorice, (Glycyrrhiza spp.)which is yet another member of the pea family. While there is a growing belief among herbalists, botanists, and medical researchers that North American Milk Vetch (Astragalus americans – a common weed), may have similar medicinal attributes and may even be the exact same plant as A. membranaceous; the medicinal astragalus of commerce. However, the Astragalus genus is very large, consisting of hundreds of species, which in many cases are very difficult to differentiate, even by trained botanists. Some varieties of astragalus are toxic, and to compound this mystery even more, these plants will often cross-pollinate and hybridize. For now, the jury is still out on whether or not we have a wild, medicinal astragalus in North America.
Habitat & Range: An import from China, astragalus has been cultivated throughout much of the world as an important herb of commerce.
Cycle & Bloom Season: A perennial that blooms from spring to early summer.
Parts Used: The mature (3+ year old) roots.
Actions: Immunostimulant, antiviral, anti-inflammatory, hypothyroid (mildly depresses thyroid function), hypotensive, alterative, digestive tonic.
Affinities: Immune system, lungs, liver, heart, kidneys, thyroid, digestive tract.
Preparation: Tincture or infusion.
Specific Uses: One of best known and widely used herbs in Chinese Medicine (where it is known as “Huang Qi”), astragalus has found its way into Western Herbalism by virtue of its widely versatile immune-strengthening qualities. In Chinese Medicine, astragalus root is sweet and mildly warm. It tonifies the Qi and hoists Yang. It is commonly used for Spleen-Lung Qi deficiency, including symptoms of emaciation, weariness, shortness of breath, loss of appetite, diarrhea, and prolapse of the uterus or anus1.
Astragalus is especially useful for strengthening the body against viral infections of the respiratory tract and heart through stimulation of killer-cell activity and interferon production in the body, and it imparts direct antibacterial and anti-inflammatory qualities to this effort as well. This makes astragalus a viable option for early treatment of various forms of respiratory infection, including kennel cough (Bordetella bronchiseptica), a condition which theoretically involves this bacteria’s opportunistic cooperation with various forms of virus. While astragalus works to stimulate T-cell activity and helps to raise white blood cell counts2,3, it also boosts the body’s defenses through its liver-strengthening attributes. In a study involving rats (again, we oppose animal studies), saponin constituents were shown to enhance DNA synthesis in the liver— a process which is believed to be a major factor in the strengthening of cell structures against infection or the introduction of toxins4. Other studies suggest that astragalus may be useful for helping the body protect itself and speed recovery from the damaging effects of long term steroid therapies5. Astragalus is known to strengthen kidney circulation, making it useful in early stages of kidney infection and/or renal failure6.
For any of the aforementioned purposes, up to 20 drops of the extract can be administered for each 20 lbs. of your animal’s body weight; up to twice daily.
In addition to its broad-spectrum ability to boost resistance to disease, astragalus is traditionally used to boost energy levels in debilitated people and animals, which adds to its promise as a candidate in the treatment of various cancers; especially those which are compounded by depressed immune functions. For pet owners who are going through the horrors of chemotherapy or radiation treatments for their animals, astragalus may offer a foot hold in maintaining some functional balance in an immune system that is stressed by both a disease and toxic intervention. To use astragalus in this capacity, first consult a holistic veterinarian.
Astragalus is also known to have antiviral qualities that are specific to infections of the heart. Again, if you suspect a problem of this serious nature, talk to a holistic veterinarian.
Availability: Astragalus is available through most good herb retailers. The seed can be purchased from specialty seed catalogs.
Propagation & Harvest: Astragalus is very easy to grow from seed— some rich soil, full sun, and ample watering is all it requires to thrive. However, if you decide to grow this plant in your garden, chose a place where it can remain for quite some time. Astragalus roots require three or more years to reach their full medicinal potential, and during this time, the plants will likely spread throughout the area where they were planted. Do not plant astragalus unless you are certain that the seed you have is in fact A. membranaceous, and do not plant astragalus if you live in an area where soils have a high selenium content (see “Cautions and Comments”).
Alternatives and Adjuncts: For respiratory infections, astragalus combines well with coltsfoot, grindelia, or mullein leaf. For kidney infections or dysfunction, couchgrass, cornsilk, pipsissewa, and goldenrod are noteworthy adjuncts. For use in situations involving liver toxicity, cancer, or depressed immune functions, gentle tonic herbs with diuretic, alterative, and nutritive qualities are indicated to help remove toxins and excess waste from the body. Dandelion, burdock, red clover, licorice, and alfalfa are excellent herbs to investigate.
For an overactive thyroid, astragalus works well by itself, but if you don’t have access to any, an alternative choice might be the herb, bugleweed.
Cautions & Comments: While Astragalus membranaceous ; the medicinal variety of astragalus is among the safest of medicinal herbs for both humans and animals, many other species of astragalus are toxic, especially to grazing animals. Buy astragalus roots, preparations, and seeds only from reputable sources. Also, astragalus is known to accumulate selenium in its tissues, in areas where a high selenium content is present in the soil. Selenium can be very toxic in high doses. Check with your county extension agent before planting this herb.
Although this herb is commonly used to treat immune disorders, its use may be contraindicated in disorders where immune responses are abnormally increased and/or counter-productive. For more information on this, see “Echinacea”.
In Chinese Medicine, astragalus is contraindicated in Excess Heat and Yin Deficiency patterns.
1. Schoen, Allen, Wynn, Susan. Complementary and Alternative Veterinary Medicine,
2. Weng, X.S. ,Chung, Kuo, Chung, Hsi I., Chieh, Ho Tsa Chih. “Treatment of leucopenia with pure Astragalus preparation–an analysis of 115 leucopenic cases” Wuxi TCM Hospital, Jiangsu. 1995 Aug, 15:8, 462-4.
3. Chung, Hsi I., Chieh, Ho Tsa Chih,Chang, C.Y., Hou, Y.D., Xu, F.M. “Effects of Astragalus membranaceus on enhancement of mouse natural killer cell activity” Clin Lab Immunol. 4(8):484-485, Aug., 1984.
4. Zhang, N.D., Wong, W.L., et al. “Effects of astragalus saponin 1 on cAMP and cGMP level in plasma and DNA synthesis in regenerating rat liver.” Acta Pharmaceutica Sinica, 19(8), 619-621, 1984.
5. Yang, G., and Geng, P. “Effects of yang-promoting drugs on immunological functions of yang-deficient animal induced by prednisolone.” Journal of Traditional Chinese Medicine, 4(2), 153-156, 1984.
6. Dong, D.C., Zhou, L.F., and Chen, J.X.J. “Changes in proteinuria, renal function and immunity after treatment with injections of a solution of Astragalus membranaceus.” 25(3):119-23, March, 1988.