A spiny herbaceous plant, milk thistle produces a flavonoid complex known as silymarin. People have used the seeds of milk thistle medicinally for more than 2,000 years to take advantage of the silymarin. The complexes found within the seeds of milk thistle, according to the Mayo Clinic, have been used to treat gastrointestinal, gall bladder and liver conditions. Separating the seeds from the spiky hairs of a milk thistle plant is a difficult process because of the spikes. However, you can easily remove the seeds and cure them yourself to prevent them from pricking your fingers.
Clip the tops of the seeded heads from your growing or fresh-cut milk thistle plants.
Place the cut seeded heads in a brown paper sack and allow them to dry in the sack for about a week.
Place the paper sack on your counter or outdoors on asphalt.
Use a rolling pin to lightly apply pressure to the dried milk thistle flower heads within the bag. This causes the seed heads to crack open and release the seeds.
Pour the contents of the bag over a sifting screen, then place the bag beneath it. The bag will catch the seeds as you sift through them on the sifting screen. The seeds are tiny enough to fit through the screen whereas the hairs and other large bits cannot fit.
Brush the debris such as the hairs and brittle bits of flower casing away from the tiny seeds of the milk thistle flower.