Silymarin is the active component of milk thistle. Silymarin is a flavonoid complex consisting of silibinin, silychristin, and silydianin. Silibinin (also known as silybin) is the major active component of the silymarin complex and is credited with giving milk thistle its beneficial properties.

This ancient healing herb serves many different purposes including:

Antioxidant: Silymarin works as an antioxidant to protect hepatic (liver) cells from damage from a variety of diseases and also helps repair and regenerate these cells. If cells have been damaged by free radicals, silymarin encourages the liver to increase the enzymes and proteins needed to heal the cells. It works by altering the structure of the cell membrane in order to prevent toxins from entering the cell thereby causing damage.

Phytonutrient: Acting as a phyotonutrient silybin also provides a variety of benefits including anti-inflammatory, anti-carcinogenic and cardiovascular benefits. Milk thistle seems to be a "smart herb," since it is able to enhance the activity of certain enzymes while inhibiting the activity of others. For example, it can encourage growth of good cells where needed, such as in the event of hepatitis or other liver damage, but it can also arrest the growth of bad cells such as cancer cells