Milk Thistle

Scientific name: Silybum marianum

Fact Box:

  • Order: Asterales
  • Family: Asteraceae
  • Genus: Silybum
  • Species: S. marianum


Also known as blessed thistle, Silybum marianum is a weedy, biennial flower that is native to the Mediterranean region. Purple flower heads with spiky bracts and prickly, white-veined leaves are the milk thistle’s signature features, and the plant’s height can vary from 2 feet to 6.5 feet.


Younger flowers and leaves (with spikes removed) can be cooked and eaten as vegetables, and the flower heads can be soaked in water to make tea. Milk thistle seeds can also be used like sunflower or flax seeds in baked goods or as snack. However, milk thistle is most well known for its medicinal properties. The silymarin substance in milk thistle extract can be used to protect your liver and bones, lower blood sugar levels, prevent some types of brain damage, help in the cancer treatment process, and more!


At the same time, though, milk thistle can sometimes be toxic to livestock, especially when consumed in large amounts. This prickly plant also spreads quickly and is considered invasive in many areas. For example, it is illegal to buy or sell milk thistle in Washington state! This is why it is often recommended to cut off flower heads before the seeds begin to spread.