Silymarin is a flavonolignan complex that is isolated from the fruits of the milk thistle, Silybum marianum. It consists mainly of silibinin, silychristin and silydianin - compounds that are characteristic of this plant. Silymarin is considered the defining main ingredient of milk thistle and has been described in botany for centuries. In modern formulations, it is used as a plant extract with a high content of characteristic polyphenols and complements the overall profile of functional micronutrient preparations with a traditional, secondary plant component.