Centaurea cyanus, known as cornflower, bachelor’s button, or bluebottle, is an annual flowering plant native to Europe and naturalized in many other regions worldwide. The young shoots and flowers are edible and can be used to obtain edible blue dye. Cornflowers are also used as herbal teas. Traditionally, cornflower was used as an herbal medicine to treat conjunctivitis and as a wash for tired eyes. The flowers are known to be antipruritic, antitussive, and astringent. The blue pigment from blue cornflower is an anthocyanin called protocyanin.