Isatis tinctoria (also known as dyer’s woad), is a member of the Brassica family. Although native to the grasslands of southeastern Russia, it spread widely across Asia and Europe by cultivation, and is considered a noxious weed in most of the western United States. In addition to its medicinal use, Isatis has a long history of use as an indigo dye. Isatis is a commonly used herb in traditional Chinese medicine. Root extracts of the herb are known as Ban Lang Gen and leaf extracts are known as Da Qing Ye. An indigo dye extract containing other herbs in addition to Isatis is referred to as Qing Dai. Documented medicinal use of Isatis in the western tradition extends back to at least the first century A.D. Both the leaves and roots have been used medicinally.