For centuries, this herbal preparation commonly known as milk thistle has been recognised for its special properties. Silymarin, the active extract from the seeds of the milk thistle, may help to maintain a healthy liver - the organ which is so vital to maintain body health. In addition to metabolising fats, proteins, carbohydrates and the storage of some vitamins, the liver metabolises alcohol and inactivates toxic substances. Milk thistle may also help to to maintain a healthy circulation. Milk thistle acts to neutralise free radicals formed in the body and exerts a protective effect.