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Centaurea cyanus
CautionKornblume · (Centaurea cyanus)
Daisy family (Asteraceae)
Description
Its intense cornflower blue, produced by the pigment complex protocyanin, once made this common cornfield weed a symbol of pastoral romance and a popular ingredient in decorative tea blends such as Lady Grey. An infusion of the dried flowers was traditionally drunk as a bitter to stimulate appetite and liver and bile function, though German Commission E assessed this indication negatively in 1989 for lack of evidence. Cool flower infusions were also used in folk medicine as an eye bath for mild conjunctival irritation — strict hygiene is essential here, since contaminated preparations near the eye can be dangerous. A more concentrated flower tea served as a gargle for mouth ulcers. Raw, the petals taste mild and work well as an edible salad garnish or natural colourant. Cornflower should be avoided by anyone with a known daisy-family allergy, as cross-reactions are possible.
Infusion of dried flowers was traditionally used as a bitter to stimulate appetite and liver and bile function. The German Commission E assessed this indication negatively in 1989 due to lack of scientific evidence.
Preparation & dosage
- Dry amount
- 1–2 g
- Doses per day
- 2×
Traditionally, cool flower infusions were used as eye baths or compresses for minor eye inflammation and conjunctival redness. Strict hygiene is mandatory; contaminated infusions are contraindicated.
Preparation & dosage
Concentrated flower infusion for rinsing in mouth ulcers and mild gum bleeding. The tannin content has an astringent effect on the mucosa.
Preparation & dosage
Sources: [3]
Historically used as a mild diuretic and diaphoretic for fever and fluid retention. These folk medicine applications are not scientifically substantiated.
Preparation & dosage
- Dry amount
- 1–2 g
- Doses per day
- 2×
Petals can be used raw in salads or as a decorative element in food. Dried flowers serve as a decorative component in tea blends (e.g. Lady Grey) and as a natural food colorant.
Sources: [2]
In folk medicine, cornflower tea was used as an emmenagogue for irregular or absent menstruation. Not scientifically substantiated.
Preparation & dosage
- Dry amount
- 1–2 g
- Doses per day
- 2×
Avoid in known Asteraceae (daisy family) allergy. Eye baths only under strict hygiene from a sterile infusion; contaminated eye applications are contraindicated. The German Commission E assessed the classical indications negatively in 1989 due to lack of evidence. ASPCA classification (accessed 2026-08-10): non-toxic to dogs and cats.
Avoid during pregnancy due to the emmenagogue folk tradition.
Insufficient safety data available.
No clinical data for children. Culinary use in small amounts is generally considered safe.
Contraindications
- Known hypersensitivity to Asteraceae (daisy family allergy).
- Eye baths in case of eye infection or injury, or where sterility of the preparation cannot be ensured.
Harvested part: flowers
- Time of day:
- Harvest flowers in the morning during dry weather, shortly after opening.
- Drying:
- Dry immediately at max. 40 °C in the dark to preserve the blue colour. Spread petals individually.
- Storage:
- 12 months — Store protected from light and airtight; light and moisture destroy colour and constituents.
- Time of day:
- Collect seeds at maturity when the flower heads have dried out.
- Drying:
- Allow flower heads to ripen further, shake out seeds, dry cool.
- Storage:
- 24 months — Dry and cool in paper bags or glass jars.
- Protocyanin (Cyanidin-Komplex)FlavonoidFlower
Anthocyanin pigment; responsible for the characteristic blue colour through complex formation with iron, magnesium, and calcium. Related to cyanidins in roses.
- QuercetinFlavonoidFlower
Flavonol aglycone; antioxidant and inflammation-modulating; occurring in the flower as a glucoside.
- ApigeninFlavonoidFlower
Flavone aglycone; gastroprotective and mildly anti-inflammatory; together with quercetin and caffeic acid derivatives responsible for the gastroprotective effect.
- LuteolinFlavonoidFlower
Flavone; antioxidant and mildly anti-inflammatory activity.
- Kaffeesäure-DerivatePhenolic acidFlower
Caffeoyl tartrate and further caffeic acid esters; antioxidant; described together with flavonoid aglycones for gastroprotective effects.
- N-FeruloylserotoninOtherFlower
First isolated from Centaurea cyanus in 2001; inhibits COX-2 and 5-LOX as well as chemokine ligands CCL17 and CCL22 in vitro; anti-inflammatory properties.
- Fettsäuren (fettes Öl im Samen)OtherContent: bis 28 %Seed
Seeds contain a high proportion of fixed oil (up to 28 %); not used medicinally but botanically noteworthy.
- [3]MonographCentaurea cyanus — Plants For A Future (PFAF)(accessed: 2026-05-22)
- [1]WikipediaKornblume (Wikipedia DE)(accessed: 2026-05-22)
- [2]WikipediaCentaurea cyanus (Wikipedia EN)(accessed: 2026-05-22)