Astragalus membranaceus (Latin); membranous milkvetch root (English), huang qi (Chinese), ogi (Japanese), and hwang gi (Korean) is one of the important “Qi tonifying” adaptogenic herbs from the Chinese materia medica. The Chinese species A. membranaceus and the related A. membranaceus var mongholicus (synonym: A. mongholicus) are defined in the Pharmacopoeia of the People’s Republic of China as Radix Astragali. It has been prescribed for centuries for general weakness, chronic illnesses, and to increase overall vitality. The genus Astragalus is a very large group of more than 2,000 species distributed worldwide, and is commonly known as milkvetch root. Currently, much of the pharmacological research on Astragalus is focused on its immune-stimulating polysaccharides and other active ingredients useful in treating immune deficiency conditions. Astragalus has demonstrated a wide range of potential therapeutic applications in immunodeficiency syndromes, as an adjunct cancer therapy, and for its adaptogenic effect on the heart and kidneys. Astragalus root has been used to promote immune function and as a tonic to build stamina. Ancient Chinese texts record the use of Astragalus for tonifying the spleen, blood, and qi.