Astragalus and Warfarin
Astragalus is a medicine for patients with compromised immune systems. It falls into the category of dietary supplement and therefore not regulated by the Food and Drug Administration as a medication. Astragalus is GRAS (generally regarded as safe) however; this does not mean it is safe to use with warfarin.
According to the National Institutes of Health, astragalus products are derived from the roots of Astragalus membranaceus or related species, which are native to China. In traditional Chinese medicine, astragalus is commonly found in mixtures with other herbs, and is used in the treatment of numerous ailments, including heart, liver, and kidney diseases, as well as cancer, viral infections, and immune system disorders. Western herbalists began using astragalus in the 1800s as an ingredient in various tonics. The use of astragalus became popular in the 1980s based on theories about anti-cancer properties, although these proposed effects have not been clearly demonstrated in reliable human studies.
Based on anecdotal reports, astragalus may increase the risk of bleeding when taken with drugs that increase the risk of bleeding, such as warfarin. More frequent testing is recommended and as always, talk to your doctor before stoping or starting any supplements.