Woad also called Dyer’s woad, or Glastum, Woad is also the name of a blue dye produced from the leaves. Since ancient times and until synthetic blue dyes took over, woad was an important source of blue dye and was cultivated throughout Europe, especially in Western and Southern Europe. In medieval times there were important woad-growing regions in England, Germany and France. Woad has also been used in traditional Chinese medicine for centuries. Production of woad is increasing in the UK for use in inks, particularly for inkjet printers.