Astragalus (Astragalus membranaceus) is an amazing herb backed by tradition and supported by science. Oriental medicine has used it for thousands of years and is called variously Beg Kei, Bei Qi or Hwanggi. Fortunately I don't have to pronounce these as Astragalus grows abundantly in the United States. Here the common names are Membranous Milk Vetch, Astragali, Tragacanth or simply Astragalus.
The old herbalists classified this one as a bidirectional herb and only used the root of the plant. The old ones rightfully considered it to be immunotonic and cardiotonic, "tonic" meaning anything that strengthens.
Nutritionally, modern science knows Astragalus contains choline, calcium, copper, magnesium, manganese, potassium and selenium. Chemical constituents include betaine, beta-sitosterol, formononetin, a wide variety of fatty acids, saponins, isoflavanoids and polysaccharides. This is a powerful plant.
A good deal of science supports the use of this inexpensive herb since the advent of HIV. The herb was an "underground" treatment for a long while. These days, it is regarded as a powerful and proven supporter of the immune system, reducing colds and flus and helping to kill cancer cells. It has the ability to kill the virus that causes myocarditis (inflammation of the heart).
It also helps the heart to pump stronger and improves cardiac and renal functions. Chest discomfort and breathing difficulty are helped in people with heart failure. The herb improves digestion, too. Medical studies proved benefit on the small bowel causing stronger contractions. Wow, add to all of the above that Astragalus protects the liver, improves memory (especially in alcoholics) and shows big reductions of symptoms and recovery from chemotherapy and radiation therapy.
One last thing which could be good or bad depending on your circumstance, it improves sperm motility up to 146 percent according to one report.
This herb has only three cautions. First, it should be used cautiously or not at all with autoimmune disorders. Second, don't overdo the dosage (though that would be difficult) as selenium levels can get too high. Third, for heaven's sake if you don't want to impregnate your lady - don't use this herb!