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Cnicus benedictus flor.jpg
Scientific classification edit
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Asterales
Family: Asteraceae
Subfamily: Carduoideae
Tribe: Cynareae
Genus: Cnicus
C. benedictus
Binomial name
Cnicus benedictus
  • Cnicus microcephalus Boiss.
  • Cnicus pseudo-benedictus Asch.
  • Epitrachys microcephala K.Koch

Cnicus benedictus (St. Benedict's thistle, blessed thistle, holy thistle or spotted thistle), is a thistle-like plant in the family Asteraceae, native to the Mediterranean region, from Portugal north to southern France and east to Iran. It is known in other parts of the world, including parts of North America, as an introduced species and often a noxious weed. It is the sole species in the monotypic genus Cnicus. Other species once included in the genus have largely been reclassified to Cirsium, Carduus, and Centaurea.

The related genus Notobasis is included in Cnicus by some botanists; it differs in slender, much spinier leaves, and purple flowers.


It is an annual plant growing to 60 cm tall, with leathery, hairy leaves up to 30 cm long and 8 cm broad, with small spines on the margins. The flowers are yellow, produced in a dense flowerhead (capitulum) 3–4 cm diameter, surrounded by numerous spiny basal bracts. Blessed thistle blooms mid summer to early fall.

All parts of the plant have a light down covering. This plant has a sprawling habit instead of standing upright. It needs full sun to grow and good soil drainage, as it will die in waterlogged soil. Water blessed thistle daily if you want your plant to produce lush leaves.

Seeds are too large to start in most seed trays, so it is recommended to sow outside after the danger of frost passes.[2] Bury the seed 1/4 inch in the soil which should remain most until germination that takes between two to three weeks. Leave at least 12 to 15 inches of space between plants.

In literature[edit]

In Shakespeare’s comedy Much Ado About Nothing, “Carduus Benedictus”, in tincture form, is recommended for a cold.[3] The pointed allusion, by Margaret, is to Beatrice’s tormentor-lover, Benedict.

Edibility and medicinal use[edit]

These thistles are not considered edible, unlike Cirsium, Arctium and Onopordum species; the leaves are considered unpalatable if not bitter.

Blessed thistle is mostly used for medicinal purposes. Cnicin, the main component in this herb, is considered to have antibacterial properties, and to be anti-cancer and anti-inflammatory. This plant was used to treat the Black Plague during the Middle Ages.[4] Now it is mostly used as a galactagogue with other herbs to increase breast milk supply.[5] It is also used to aid the digestive system and detoxify the liver just like milk thistle.

Blessed thistle can help neutralize bacteria such as E. Coli, Staphylococcus aureus, and Bacillus subtilis. Cnicin blocks the enzymes necessary for bacteria replication so they are not able to reproduce and die.[6]

19th century illustration


  1. ^ "The Plant List".
  2. ^ "Grow Blessed Thistle for its Beautiful Yellow and Red Flower Crown of Thorns - Herba Medicine". 19 February 2020. Retrieved 2021-11-21.
  3. ^ Phillips, Roger (1990). The Random House Book of Herbs. Random House. pp. 173. ISBN 9780679732136. Retrieved 1 September 2019. Much Ado About Nothing.
  4. ^ "Health Benefits of Blessed Thistle can Cure it All, Even the Plague!". Herba Medicine. 2021-11-13. Retrieved 2022-05-21.
  5. ^ "Blessed Thistle", Drugs and Lactation Database (LactMed), Bethesda (MD): National Library of Medicine (US), 2006, PMID 30000834, retrieved 2022-05-21
  6. ^ Steinbach, Anke; Scheidig, Axel J.; Klein, Christian D. (2008-08-01). "The Unusual Binding Mode of Cnicin to the Antibacterial Target Enzyme MurA Revealed by X-ray Crystallography". Journal of Medicinal Chemistry. 51 (16): 5143–5147. doi:10.1021/jm800609p. ISSN 0022-2623. PMID 18672863.

External links[edit]