Holy Thistle plant - Cnicus Benedictus syn. Carbenia Benedicta, Carduus Benedictus (Asteraceae)

Medicinal Use of Holy Thistle – Cnicus Benedictus syn. Carbenia Benedicta, Carduus Benedictus (Asteraceae)


Erect, red-stemmed annual growing to 26 in (65 cm). Has spiny leathery leaves, a spiny stem, and yellow flowers in summer and autumn.

Habitat & Cultivation

This Mediterranean plant flourishes on dry stony ground and in open areas. The leaves and flowering tops are collected in summer.

Parts Used

Leaves, flowering tops.


Holy thistle contains lignans, sesquiterpene lactones (including cnicin), volatile oil, polyacetylenes, flavonoids, triterpenes, phytosterols, and tannins. Cnicin is bitter and anti-inflammatory; the volatile oil is thought to have antibiotic properties.

History & Folklore

In the Middle Ages, holy thistle was thought to cure the plague. In his herbal of 1568, Nicholas Turner wrote: “There is nothing better for the canker [ulcerous sore] and old rotten and festering sores than the leaves, juice, broth, powder, and water of holy thistle.”

Medicinal Actions & Uses

Holy thistle is a good bitter tonic, stimulating secretions within the salivary glands, stomach, gallbladder, and intestines, and thereby improving digestion. It is taken, generally as a tincture, for minor digestive complaints. It has also been a treatment for intermittent fevers. Holy thistle is mildly expectorant and antibiotic. It makes a healing balm for wounds and sores.


In excessive doses, holy thistle may cause vomiting. It is subject to legal restrictions in some countries.