Natures Aid Milk Thistle Tablets Contain Milk Thistle Extract Which Provides 120Mg Of Silymarin-A Bioflavanoid Able To Alter The Cell Membranes Of Liver Cells Thus Inhabiting The Passage Of Toxins. Milk Thistle Has Been Used For Centuries As A Natural Way To Protect The Liver Against Toxins And Help Keep It Healthy.