Milk Thistle is a herbal liver protector and can protect the liver in many ways. Milk Thistle's active ingredient is silymarin which protects the liver at the level of individual cells. Milk Thistle is also a potent antioxidant slowing the inflammatory response helping to prevent further liver damage. Milk Thistle can be beneficial for those pets on daily medications which are metabolized by the liver or damaged livers. Milk Thistle may also be useful for problems which are related to the liver such as skin conditions, gastrointestinal upsets and dysfunctions in the immune or hormonal systems.