Milk thistle.
Article Type: Report
Subject: Milk thistle (Health aspects)
Seeds (Physiological aspects)
Seeds (Research)
Pub Date: 09/22/2011
Publication: Name: Annals of the American Psychotherapy Association Publisher: American Psychotherapy Association Audience: Academic; Professional Format: Magazine/Journal Subject: Psychology and mental health Copyright: COPYRIGHT 2011 American Psychotherapy Association ISSN: 1535-4075
Issue: Date: Fall-Winter, 2011 Source Volume: 14 Source Issue: 3
Topic: Event Code: 310 Science & research
Product: Product Code: 0181110 Seeds NAICS Code: 11142 Nursery and Floriculture Production
Geographic: Geographic Scope: United States Geographic Code: 1USA United States
Accession Number: 277270198


Milk thistle is a flowering herb that is native to the Mediterranean region. It has been used for thousands of years as a remedy for a variety of ailments, especially liver problems,

How Milk Thistle Is Used

Silymarin, which can be extracted from the seeds (fruit) of the milk thistle plant, is believed to be the biologically active part of the herb. The seeds are used to prepare capsules, extracts, powders, and tinctures.

What Milk Thistle Is Used For Milk thistle is believed to have protective effects on the liver and improve its function. It is typically used to treat liver cirrhosis, chronic hepatitis (liver inflammation), and gallbladder disorders. Treatment claims also include:

* Lowering cholesterol levels

* Reducing insulin resistance in people with type 2 diabetes who also have cirrhosis

* Reducing the growth of cancer cells in breast, cervical, and prostate cancers.

Side Effects and Cautions

In clinical trials, milk thistle appears to be well tolerated in recommended doses. Occasionally, people report various gastrointestinal side effects.

Milk thistle can produce allergic reactions, which tend to be more common among people who are allergic to plants in the same family (for example, ragweed, chrysanthemum, marigold, and daisy).

Milk thistle may lower blood sugar levels. People with diabetes or hypoglycemia, or people taking drugs or supplements that affect blood sugar levels, should use caution.

Patients should tell all their health care providers about any complementary and alternative practices they use. This will help ensure coordinated and safe care.


What the Science Says

Laboratory studies suggest that milk thistle may benefit the liver by protecting and promoting the growth of liver cells, fighting oxidation (a chemical process that can damage cells), and inhibiting inflammation. Results from clinical trials of milk thistle for liver diseases have been mixed, and most studies have not been rigorously designed. Reviews of the research have concluded that the efficacy of milk thistle against liver disease has not been established, and additional, high-quality trials are needed.

The Hepatitis C Antiviral Long-Term Treatment Against Cirrhosis (HALT) study, sponsored by NIH, found that silymarin use by hepatitis C patients was associated with fewer and milder symptoms of liver disease and somewhat better quality of life, but there was no change in virus activity or liver inflammation.

NCCAM-funded research includes a number of studies on milk thistle for liver disease, such as a phase II trial to better understand the use of milk thistle for chronic hepatitis C. A study cofunded by NCCAM and the National Institute of Diabetes and Digestive and Kidney Diseases is examining the effects of milk thistle on people with chronic hepatitis C who have not responded to conventional antiviral treatment, and people with nonalcoholic steatohepatitis (liver disease that occurs in people who drink little or no alcohol).

The National Cancer Institute is studying the effectiveness of silymarin for patients with leukemia who experience chemotherapyrelated liver damage. The National Institute of Nursing Research is investigating whether milk thistle is an effective treatment for hepatitis C in people with both hepatitis C and HIV.


Effects of Milk Thistle

Extract on the Hepatitis C

Virus Lifecycle

A laboratory study suggests that silymarin--an extract from the milk thistle plant--has multiple effects against the life cycle of the hepatitis C virus. Hepatitis C is a chronic (long lasting) disease that primarily affects the liver and is often difficult to cure. The laboratory study examined the antiviral properties and mechanisms of silymarin on cultured (grown in a lab) human liver cells infected with the virus. The study, funded in part by NCCAM, was published in the journal Hepatology.

The researchers grew human liver cells and infected them in vitro with the hepatitis C virus. The cells were then exposed to either standard hepatitis C drug treatment or to a diluted dose of silymarin. By analyzing the interactions between silymarin and the virus, the researchers observed that silymarin prevented the entry and fusion of the hepatitis C virus into the target liver cells. They also found that silymarin inhibited the ability of the virus to produce RNA (a chemical that plays an important role in protein synthesis and other chemical activities of the cell), interfering with a portion of the virus's lifecycle. When measured against untreated cells, silymarin also significantly decreased viral load (the amount of virus in the cells), although to a lesser degree than treatment with interferon did. The researchers also found that silymarin prevented the cell-to-cell spread of the virus.

These findings build on previous research of silymarin's antiviral and anti-inflammatory properties and provide more information about the potential mechanisms involved in silymarin's antiviral actions. Further research, particularly in clinical trials, is needed to determine if silymarin could be a safe and effective supplement for treating hepatitis C in humans.


Wagoner J, Negash A, Kane OJ, et al. Multiple effects of silymarin on the C virus lifecycle. Hepatology, 2010;51 (6):1912-1921.


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Milk thistle fruit. In: Blumenthal M, Goldberg A, Brinckman J, eds. Herbal Medicine: Expanded Commission E Monographs. Newton, MA: Lippincott Williams & Wilkins; 2000:257-263.

National Center for Complementary and Alternative Medicine. CAM and Hepatitis C: A Focus on Herbal Supplements. National Center for Complementary and Alternative Medicine Web site. Accessed at hepatitisc/ on June 3, 2010.

Rambaldi A, Jacobs BP, Gluud C. Milk thistle for alcoholic and/or hepatitis B or C virus liver diseases. Cochrane Database of Systematic Reviews. 2007;(4):CD003620.

Seeff LB, Curto TM, Szabo G, et al. Herbal product use by persons enrolled in the hepatitis C antiviral long-term treatment against cirrhosis (HALT-C) trial. Hepatology. 2008;47(2):605-612.
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