This plant is named for the white lines that streak across its green leaves. If the leaves are ripped or crushed, a milky white liquid oozes out. You might also hear it called Mary thistle or holy thistle.

Source:-https://www.reddit.com/r/ImmunitySupplements/comments/o7g6si/does_milk_thistle_help_your_liver_how_do_you_take/