Astragalus (Astragalus membranaceus)
by Krystal Thompson
“It is in great repute as a tonic, pectoral, and diuretic medicine, the disease for which it is prescribed, therefore, are almost numberless.” - G. A. Stuart, Chinese Materia Medica, 1911
Other Names: Huang Qi (Chinese), Milkvetch, Yellow Leader
Description/Taxonomy: Astragalus is both the common name of the particular herb that we’re going to explore here, as well as the name of the very large genus to which the herb belongs. All belonging to the Fabaceae (legumes, peas, beans) family, the thousands of non-medicinal Astragaluses are often called “milkvetches,“ such as Astragalus canadensis known as Canadian milkvetch, or Astragalus kentrophyta known as spiny milkvetch. These milkvetches include an incredible span of ornamental, edible, and poisonous plants. In addition to being incredibly large and varied, this genus also literally spans across the globe. In Europe there are 133 known Astragalus species, and in North America alone there are 368 (8)! But when we’re talking about medicinal Astragaluses, we’re likely talking about Astragalus propinquus, Astragalus membranaceus, or Astragalus mongholicus. These medicinal varieties are perennial flowering plants with hairy stems that grow to between 16 and 36 inches tall. Their leaves are made up of 12 to 18 pairs of leaflets, and sport small yellow flowers that grow in elongated spikes. These medicinal varieties are native specifically to Mongolia, Korea, and the northern and eastern regions of China.
History, Ethnobotany, and Folklore: Astragalus membranaceus is known in China as Huang Qi, meaning “yellow leader.” This name refers to both the colored interior of the root and the plant’s position of prestige among Chinese medicine practitioners. Astragalus is thought to have been used medicinally in China for at least 2,000 years, with its first text appearance in the TCM classic Shen Nong Ben Cao Jing (The Divine Farmer’s Materia Medica Classic). This text is the foundation of TCM, and within it herbs were arranged by type of material (herb, tree, etc), and then graded into categories of potency: upper, middle, and lower. Astragalus was listed in the highest class.
No doubt based on this ancient classification, astragalus is still one of the fifty fundamental herbs used in TCM, and listed as an official drug in the modern Pharmacopoeia of the People’s Republic of China. Astragalus is administered primarily as a Qi tonic, though daily prescription is also common. It is taken as a tea during times of illness to speed recovery, as well as often administered to tonify the lungs and as support for frequent colds (7). As mentioned before, there are a few different species that are grouped together under the name of common medicinal astragalus, each of which are accepted interchangeably throughout various regions of China.
In 1925, Astragalus membranaceus was introduced to North America through the USDA’s Plant Introduction Office via the Botanical Garden in St. Petersburg (8). However, in his book Herbal Antibiotics, Stephen Buhner suggests that astragalus “was not used in Western botanic practice until the tremendous East/West herbal blending that began during the 1960s.” Regardless of when exactly it became widely incorporated, it is now one of the primary immune tonic herbs in the Western pharmacopoeia, and widely available throughout the United States, both as seed and dried, prepared root.
Parts Used: Root.
Cultivation and Harvest: Astragalus seeds are small and kidney shaped. Like many other legume seeds, they have a relatively hard outer casing. Some propagators suggest slightly tarnishing this hard exterior by nicking the seeds or gently rubbing them between two pieces of sandpaper, then soaking in water overnight. Once germinated, seeds can be planted outside after the last spring frost, and should sprout within 2-3 weeks (8). The plant prefers sandy, well-drained soil, and quite a bit of bright sun exposure. Though generally hardy, astragalus doesn’t handle root disturbance well, and is best planted in its final position while still relatively small.
Roots are typically harvested once the plant has reached four years in age. Before completely dry, roots are most commonly sliced diagonally or lengthwise and sold in the shape of tongue depressors. Astragalus is also sometimes available in a finely shredded form that is quite fluffy and resembles slippery elm. If I’m cooking with astragalus in a stock or bone broth, I personally prefer the tongue depressor shape. But if I’m making tea or tincture, I find the shred cut to be a bit easier to work with.
Herbal Actions: Adaptogen, antibacterial, antiviral, diuretic, immune-stimulant, vasodilator.
Constituents: Saponins, polysaccharides, triterpenoids, isoflavones, glycosides.
Energetics and Taste: Sweet, warm.
Meridians/Organs Affected: Spleen, lungs.
Medicinal Use: Tonifying and stimulating, astragalus is often affectionately called the “young person’s ginseng.” Though it is a relatively new focus in eclectic American herbalism, astragalus is getting some serious clout as of late for being an adaptogen, an herb that has some normalizing activity, particularly on the immune, nervous, and hormonal systems. Prior to this classification, astragalus was primarily prized for its immunomodulating, diuretic, antibacterial, and antiviral properties. Let’s further explore how each of these express themselves within the plant and within our bodies.
Astragalus’s antiviral action in combination with its immuno-supportive properties make it a top choice as a preventative ally for colds and upper respiratory infections, as well as viral conditions such as shingles, where it would, in effect, both stimulate the immune system and reduce the activity of the virus (4). It is also a wonderful ally for long-term preventative support against this and other viral conditions. The combination of antiviral and anti-inflammatory properties with astragalus’ immunostimulating effects further work together to prevent infection. The polysaccharides in astragalus intensify white blood cell activity, stimulate pituatary adrenal-cortical activity, and restore depleted red blood cell formation in bone marrow (6). In other words, astragalus increases the bone marrow reserve, supporting the immune system in its fight against pathogens by stimulating the production of defense cells (2).
This immunostimulating activity was widely studied in China in the 1970’s and 80’s. Blending the strengths of both modern and traditional herbal medicine, researchers wanted to find out if Astragalus would benefit patients receiving chemotherapy treatments. The plant was found to act as a non-specific immune system stimulant, actively supporting the production of white blood cells where they would normally be exceptionally low. It was also found to significantly modify gastrointestinal toxicity of patients going through chemotherapy, as well as stimulate the appetite where it would normally be depressed or made nearly non-existent by the treatment. Later studies in the United States continued on this research in exploring astragalus as a support for those with immune systems weakened by chemotherapy or radiation, with similar positive results further suggesting that astragalus helped these patients recover more quickly. This fantastic immunostimulating effect is often primarily attributed to the polysaccharides found in astragalus, though there is reason to believe that the saponins and triterpenes also play a role. In TCM, these benefits would be called “fu-zheng”: herbal therapies that treat disease by enhancing or promoting the host defense mechanism, and/or normalizing the central energy (8).
Astragalus contains high concentrations of antioxidants, which help to protect cells against damage from oxidative stress, as well as support the cardiovascular system. Recent Chinese studies have shown that astragalus may also benefit cholesterol levels, improve cardiovascular function, and lessen symptoms of severe heart disease (1). Astragalus has also been shown to prevent kidney and liver damage caused by medication and viruses (5).
In his book Healing Lyme, Buhner makes the powerful suggestion of using astragalus regularly to prevent Lyme disease. However, he warns against use by anyone suffering from late-stage Lyme disease, as it could exacerbate an autoimmune response to an undesirable level. Lastly, astragalus can be beneficial to us in regulating metabolism of dietary sugars, and thus can be helpful to those with diabetes (9).
Allies: Astragalus is often blended with other immune tonics such as ligustrum, or privet, and reishi. Pair with goldenseal and echinacea for acute viral outbreaks (4). In the 1531 Chinese text Medical Case Book of the Shi-shan, astragalus is suggested to be paired with Panax ginseng as a tonic for fatigue, general debility, lack of appetite, and spontaneous sweating (8).
Cautions and Contraindications: Astragalus is contraindicated for those with acute infections. Those with autoimmune conditions should speak with their healthcare provider before using astragalus, as it may stimulate immune function. Similarly, it may also interfere with drugs that are meant to suppress the immune system.
Dosage and Method of Delivery: Tincture, capsules, decoction, and sometimes even as an injection in Asian hospitals. Capsules and decoction tend to be the primary methods of delivery for most cases, such as its common use as an immune supporter. Suggested decoction dosage is 1 cup 2-3 times daily. Suggested powdered extract dosage is 2 capsules 2-3 times daily. The root is also sometimes stir-fried in honey to enhance both its sweetness and tonic properties. My personal favorite way to get my dose of astragalus is soaked in a nutritious bone broth soup!
1. Ehrlich, Steven D., NMD. “Astragalus.” University of Maryland Medical Center, accessed online October 2016.
2. Hobbs, Christopher, L.Ac., A.H.G. “Information on Astragalus.” www.christopherhobbs.com, accessed online October 2016.
3. Hobbs, Christopher, L.Ac., A.H.G. “Herbal Adaptogens: Fitting into the Modern Age,” 2014.
4. Martin, Hillary, ND. “Naturopathic Antiviral Treatment and Pain Control for Shingles (Herpes Zoster).” Naturopathic Wellness News, 2013.
8. “Astragalus, Astragalus Membranaeus, Huang-Qi.” Steven Foster Group, 2011.