*There is a theoretical risk that milk thistle could have an estrogen-like effect, so people with hormone-sensitive conditions such as endometriosis, uterine fibroids or cancers of the breast, uterus and ovaries should avoid milk thistle, particularly the above ground parts of the plant.
*Milk thistle may reduce the effectiveness of oral contraceptives. One constituent of milk thistle can inhibit an enzyme called beta-glucuronidase, which is involved in the activity of oral contraceptives.
* Don't confuse Milk Thistle with [[Blessed Thistle]] (Cnicus Benedictus)
==The benefits of Milk Thistle are==
For many centuries extracts of milk thistle have been recognized as "liver tonics." Research into the biological activity of silymarin and its possible medical uses has been conducted in many countries since the 1960s, but the quality of the research has been uneven. Milk thistle has been reported to have protective effects on the liver and to greatly improve its function. It is typically used to treat liver cirrhosis, chronic hepatitis (liver inflammation), toxin-induced liver damage including the prevention of severe liver damage from Amanita phalloides ('death cap' mushroom poisoning), and gallbladder disorders.