Centaurea cyanus, commonly known as cornflower or bachelor’s button, is an annual flowering plant in the family Asteraceae native to Europe.

In addition to the fact that the cornflower flower can be mixed with other teas to get the blue color of the sky (the psychological aspect of herbal treatment is not negligible), the plant is effective against cough, bronchitis and liver disease; it promotes the excretion of urine in case of edema and sluggishness of the kidneys; but above all, excellent colliries against inflammation of the eyes are prepared from it. According to a kind of tradition that is probably based on the medieval way of looking at the “medicine of signs”, cornflower cures only blue eyes – and plantain cures black eyes.