- Family Asteraceae (formerly Compositae)
- Centaurea cyanus
- Centaurea, Batchelor’s Buttons, Bluebonnet, Bluebottle, Blue Centaury, Cyani, Bluebow, Hurtsickle, Blue Cap, Cyani-flowers
- None listed
Native to the Near East, cornflower now grows wild in all temperate regions, often in cornfields. It is an annual, or biennial, growing to three feet producing multi-branched stems, a basal rosette of leaves, and sky-blue flowers, which are gathered just after they open.
Cornflower's medicinal properties were first mentioned in the 12th century writings of Hildegard of Bingen. Later, the herbalist, Pierandrea Mattioli (1501-1577), recommended it on the basis of the Doctrine of Signatures, which held that a plant's appearance indicated the ailments it would cure. Since the flower's deep blue colour symbolized healthy eyes, it became a prime treatment for eye ailments — which may explain why it never caught on in countries where the eye colour is not blue!
In France, the plant is known as casse-lunette meaning "break glasses". A related species, C. scabiosa (Greater knapweed), formed part of the medieval salve, an ointment applied to wounds and skin infections.
- digestive tonic
- mild laxative
- stimulant for liver and gall bladder
- bitter principles
- mildly antibiotic
- Flowers, seeds, leaves
In France, the plant is still used as a remedy for the eyes, including conjunctivitis and inflammations. A strained infusion is used as an eyewash, and the petals are applied as a poultice.
The petals are also taken as a bitter tonic and stimulant improving digestion, as well as for possibly supporting the liver function. Poultices made from the petals can also be used for eye problems. The petals may also improve resistance to infection.
The seeds are used as a mild laxative for children.
The leaves are used in decoctions for rheumatic complaints and as a hair rinse to treat scalp eczema. A douche is used to treat vaginal candida infections.