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 can grow up to 1 meter tall and thrives in well-drained soils. Woad has been cultivated since ancient times, particularly by the Celts for its dyeing properties. The leaves contain indican, which can be processed to produce a blue pigment. Today, woad is less commonly used due to the availability of synthetic dyes, but it remains of interest in natural dyeing practices.