Astragalus, also known as milk vetch, is a type of legume. There are multiple species of astragalus, but astragalus membranaceous, in particular, possess multiple health benefits. Free radicals damage cells and are linked to many health problems associated with ageing. Astragalus helps inhibit free radicals with its antioxidant effects, thereby stimulating the immune system. Astragalus can be used as a general tonic to protect the liver, and fight bacteria and viruses.