Milk Thistle
What is it? Overview Usage Side Effects and Warnings

What is Milk Thistle?

The milk thistle plant commonly grows from 2 to 7 feet in height, with spiny leaves and reddish-purple, thistle-shaped flowers. It has also been called wild artichoke, holy thistle, and Mary thistle. Native to Europe, milk thistle has a long history of use as both a food and a medicine. At the turn of the twentieth century, English gardeners grew milk thistle to use its leaves like lettuce (after cutting off the spines), the stalks like asparagus, the roasted seeds like coffee, and the roots (soaked overnight) like oyster plant. The seeds and leaves of milk thistle were used for medicinal purposes as well, such as treating jaundice and increasing breast milk production.

German researchers in the 1960s were sufficiently impressed with the history and clinical effectiveness of milk...

Based on the extensive folk use of milk thistle in cases of jaundice, European medical researchers began to investigate its medicinal effects. It is currently used to treat alcoholic hepatitis , liver cirrhosis , liver poisoning, and viral hepatitis , as well as to protect the liver in general from the effects of liver-toxic medications. However, despite this wide usage, there is no definitive evidence that it is effective.

Standardized milk thistle extract is known as silymarin. Silymarin itself is a mixture of at least seven chemicals. The most active of these chemicals is commonly known as silibinin. But, silibinin too is, in fact, a mixture, comprising the two related substances silibinin A and silibinin B. 1 When injected intravenously, silibinin is thought to...

Safety Issues

Milk thistle is believed to possess very little toxicity. Animal studies have not shown any negative effects even when high doses were administered over a long period of time. 2 A study of 2,637 participants reported in 1992 showed a low incidence of side effects, limited mainly to mild gastrointestinal disturbance. 3 However, on rare occasions severe abdominal discomfort may occur. 4 On the basis of its extensive use as a food, milk thistle is believed to be safe for pregnant or nursing women and researchers have enrolled pregnant women in studies. 5 However, safety in young children, pregnant or nursing women, and individuals with severe renal disease has not been formally established.

No drug interactions are known. However, one report has noted that...