More rarely, it may cause nausea, bloating, gas, and upset stomach. f you have a ragweed allergy, you should also avoid
milk thistle.
Milk thistle may cause a rash or lead to severe allergic reaction.
Since milk thistle may mimic the effects of estrogen, some women should avoid this herb. This includes women who have fibroid tumors or endometriosis. Additionally, women with breast, uterine, and ovarian cancers should not take milk thistle.
This is how much I know about Milk Thistle.