Milk thistle is a one-year or biennial herbaceous plant in the family Asteraceae, belonging to the dicotyledonous plant class. Also known as Western white thistle, milk thistle, and North American milk thistle, it has antioxidant properties and can protect liver cells from free radical damage. Milk thistle has been used in Europe to treat liver disease. Annual or biennial herb, 1.2 meters tall. The stem is upright, branched, with edges, and rarely unbranched. All stem branches have white powdery coating, sparsely covered with spider silk or hair. The lotus shaped basal leaves and lower stem leaves have petioles, which are fully elliptical or lanceolate in shape, measuring up to 50 cm in length and 30 cm in width, with feather like shallow to fully lobed.