Herb Pharm prepares its Milk Thistle Extract from the pericarp (seed coat) of Silybum marianum plants which are Custom Wildcrafted in their natural wild habitat and are never fumigated or irradiated. Herb Pharm use a triple percolation process which creates, without heat, a more concentrated extract which contains the full-spectrum of Milk Thistle's silymarin flavonoids (silybin, silydianin & silychristin).