milk thistle

noun

: a tall thistle (Silybum marianum) having white-veined dark green leaves and large purple flower heads that is native to the Mediterranean region but has become naturalized elsewhere including the U.S.

also : an extract of milk thistle and especially its seeds that is held to protect the liver from damage or disease

Examples of milk thistle in a Sentence

Recent Examples on the Web

The formula is lightweight, and has vitamin C plus milk thistle to gently and effectively soften and protect the hair and scalp from UV rays. —Alanna Martine Kilkeary, Glamour, 24 June 2025

Like daikons and comfrey, milk thistle’s long, penetrating roots draw nutrients up from deep in the soil and aerate dense garden beds. —Lauren Landers, Better Homes & Gardens, 14 June 2025

The cream is formulated with key ingredients such as arctic marine ferment for improving discoloration and texture, milk thistle and bearberry extract for their smoothing benefits, and pullulan for firming and targeting loose and crepey skin. —Jessie Quinn, StyleCaster, 2 May 2025

Some notable ingredients include milk thistle, known to support liver health, and dihydromyricetin, which could increase the speed alcohol is metabolized. —Emily Burns, WWD, 31 Dec. 2024

Word History

First Known Use

1562, in the meaning defined above

Rhymes for milk thistle

• bristle
• fissile
• gristle
• missal
• missile
• nissl
• whistle
• abyssal
• dismissal
• epistle

Medical Definition

milk thistle

noun

milk this·​tle -ˈthis-əl 

1

: a tall thistle (Silybum marianum) that is the source of silymarin, has large clasping white-blotched leaves and large purple flower heads with bristly receptacles, and is native to southern Europe but has been widely introduced elsewhere including the United States

2

: an extract of milk thistle and especially its seeds : silymarin