The flowers are yellow, produced in a dense flowerhead (capitulum) 3–4 cm diameter, surrounded by numerous spiny basal bracts.

In Shakespeare's comedy Much Ado About Nothing, “Carduus Benedictus”, in tincture form, is recommended for a cold.

Blessed thistle is used in folk remedies as a galactagogue with other herbs to increase breast milk supply, although there is no scientific evidence that such use is effective.

[4] Although the leaves are unpalatable with a bitter taste, blessed thistle is used as a flavoring in alcoholic beverages, and is considered a safe ingredient for food uses.

[4] As a member of the ragweed family, blessed thistle may cause allergic reactions in susceptible people, and use of large amounts may cause stomach cramps, nausea and vomiting.