Isatis tinctoria, commonly known as woad, is a flowering plant native to Europe and parts of Asia. It belongs to the Brassicaceae family and is recognized for its bright yellow flowers and distinctive blue dye, historically used in textiles. The plant typically grows in temperate regions and can reach heights of up to 1 meter. Woad has been cultivated since ancient times, particularly by the Celts for its dyeing properties. The leaves contain a compound called indigo, which is extracted and processed to create a natural blue dye. Today, woad is also studied for its potential medicinal properties and ecological benefits.