Milk thistle (Silybum marianum), also called silybum, holy thistle, and silymarin, is a member of the Asteraceae or daisy family. Keep your liver healthy with the power of milk thistle powder. High in protein, milk thistle seeds have been used in traditional medicine for centuries. The compounds in milk thistle seeds, which are predominantly flavonoids, include silymarin, silybin, isosilybin, and silibinin. Flavonoids act as powerful antioxidants, scavenging reactive oxygen species in vivo. The flavonoid compounds found in milk thistle seeds have been extensively studied for their role in supporting liver function.