The blessed milk thistle, Silybum marianum is a tall elegant thistle, with large purple heads surrounded by spiny bracts. The leaves are dark green with dark green shiny leaves, marked with white veins. Legend tells that the white markings were caused by a single drop of milk from the Virgin Mary as she fled from Herod.

The plant has been used medicinally from ancient times and extracts are still available as a herbal medicine.