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Milk Thistle (Silybum marianum)

Be aware that the U. S. Food and Drug Administration does not strictly regulate herbs and dietary supplements. There is no guarantee of strength, purity or safety of products containing or claiming to contain valerian. Decisions to use herbs or supplements should be carefully considered. Individuals using prescription drugs should discuss taking herbs or supplements with their pharmacists or health care providers before starting.


Scientists have studied milk thistle for the following health problems:

Cirrhosis (liver disease)
Multiple studies from Europe suggest that milk thistle may improve cirrhosis and lengthen the lives of cirrhosis patients. However, most of these studies are poorly designed. Better-quality research is needed before a strong recommendation can be made.
Hepatitis (liver inflammation)
Multiple studies of milk thistle for chronic hepatitis caused by viruses or alcohol report improvements in liver tests. However, most of these studies are small and poorly designed. Better research is needed before a strong recommendation can be made.

Studies of milk thistle for acute viral hepatitis do not provide clear results. Therefore, milk thistle cannot be recommended for this potentially life-threatening condition.
Liver damage caused by toxins
There are studies of milk thistle to treat or prevent liver damage caused by drugs or toxic chemicals. Results of this research are unclear. Therefore, there is not enough scientific evidence to recommend milk thistle for this use.
High cholesterol
Laboratory and animal studies show that milk thistle may lower cholesterol. However, there are only a few studies in humans in this area, with unclear results. Therefore, there is not enough scientific evidence to recommend milk thistle for this use.
Type 2 diabetes (adult-onset diabetes)
Studies in humans of milk thistle for diabetes are low quality. Therefore, it cannot be recommended at this time.
Amanita phalloides mushroom poisoning
Several natural medicine textbooks support the use of milk thistle for Amanita phalloides mushroom poisoning, based on tradition and expert opinion. Over the past 30 years, animal research and poor-quality studies in humans have reported benefits. However, without better-quality scientific evidence, it is unclear if milk thistle is useful for mushroom poisoning.
Cancer prevention
There is ongoing laboratory research of the anticancer effects of milk thistle for breast, cervical and prostate cancer. At this time, there are not enough studies in humans to recommend milk thistle for these diseases.

Unproven Uses     

Milk thistle has been suggested for many other uses, based on tradition or on scientific theories. However, these uses have not been thoroughly studied in humans, and there is limited scientific evidence about safety or effectiveness. Some of these suggested uses are for conditions that are potentially very serious and even life-threatening. You should consult a health care provider before using milk thistle for any unproven use.

Acute liver injury
Alcoholic cirrhosis
Amiodarone toxicity reactions
Bladder cancer
Breast cancer
Breast milk stimulation
Bubonic plague
Chronic liver injury
Diabetic nerve pain
Edema (swelling)
Fatty liver
Gynecological cancers
Hepatitis C virus
Ischemic injury
Kidney damage
Kidney stones
Liver cancer
Liver "cleansing"
Liver dysfunction
Liver regeneration
Lung cancer
Menstrual problems
Primary biliary cirrhosis
Prostate cancer
Radiation sickness
Radiation toxicity
Skin cancer
Solar ultraviolet protection
Splenic disorders
Spleen diseases
Uterine complaints
Varicose veins
Work capacity

Potential Dangers     


Side Effects
Pregnancy And Breast-Feeding
Interactions with drugs, supplements and other herbs have not been thoroughly studied. The interactions listed below have been reported in scientific publications. If you are taking prescription drugs, speak with your health care provider or pharmacist before using herbs or dietary supplements.
Interactions With Drugs

Interactions With Herbs And Dietary Supplements


The doses listed below are based on scientific research, publications or traditional use. Because most herbs and supplements have not been thoroughly studied or monitored, safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients even within the same brand. Combination products often contain small amounts of each ingredient and may not be effective. Appropriate dosing should be discussed with your health care provider before starting therapy; always read the recommendations on a product's label. The dosing for unproven uses should be approached cautiously, because scientific information is limited in these areas.

Note: One study analyzing the stability of milk thistle tincture showed a shelf life of only about three months.

For Liver Diseases  Adults (Aged 18 Or Older)

For Other Conditions

The safety and effectiveness of doses for other conditions are not clear. Milk thistle has also been used intravenously, but this method of administration has not been proven safe. Milk thistle does not dissolve easily in water, therefore milk thistle tea is not recommended.

Children (Younger Than 18):  There is not enough scientific evidence to recommend using milk thistle for children.


Although milk thistle has been suggested for many conditions, the most promising uses supported by science are the treatment of cirrhosis and hepatitis. Evidence does not support the use of milk thistle for other health problems. Check with your health care provider or pharmacist before taking milk thistle if you are taking other drugs, herbs or supplements, because there may be dangerous interactions. Diabetic patients should monitor their blood sugar levels closely. Consult your health care provider immediately if you experience side effects.

The information in this monograph was prepared by the professional staff at Natural Standard, based on thorough systematic review of scientific evidence. The material was reviewed by the Faculty of the Harvard Medical School with final editing approved by Natural Standard.


  1. Natural Standard: An organization that produces scientifically based reviews of complementary and alternative medicine (CAM) topics
  2. National Center for Complementary and Alternative Medicine (NCCAM): A division of the U.S. Department of Health & Human Services dedicated to research

Selected Scientific Studies: Milk Thistle

Some of the more recent studies are listed below:

  1. Agoston M, Orsi F, Feher E, et al. Silymarin and vitamin E reduce amiodarone-induced lysosomal phospholipidosis in rats. Toxicology 2003;Aug 28, 190(3):231-241.
  2. Bass NM. Is there any use for nontraditional or alternative therapies in patients with chronic liver disease? Curr Gastroenterol Rep 1999;Feb-Mar, 1(1):50-56.
  3. Bean P. The use of alternative medicine in the treatment of hepatitis C. Am Clin Lab 2002;May, 21(4):19-21.
  4. DiCenzo R, Shelton M, Jordan K, et al. Coadministration of milk thistle and indinavir in healthy subjects. Pharmacotherapy 2003;Jul, 23(7):866-870.
  5. Ferenci P, Dragosics B, Dittrich H, et al. Randomized controlled trial of silymarin treatment in patients with cirrhosis of the liver. J Hepatol 1989;Jul, 9(1):105-113.
  6. Flora K, Hahn M, Rosen H, et al. Milk thistle (Silybum marianum) for the therapy of liver disease. Am J Gastroenterol 1998;93(2):139-143.
  7. Jacobs BP, Dennehy C, Ramirez G, et al. Milk thistle for the treatment of liver disease: a systematic review and meta-analysis. Am J Med 2002;Oct 15, 113(6):506-515.
  8. Marcelli R, Bizzoni P, Conte D, et al. Randomized controlled study of the efficacy and tolerability of a short course of IdB 1016 in the treatment of chronic persistent hepatitis. Eur Bull Drug Res 1992;1(3):131-135.
  9. Mulrow C, Lawrence V, Jacobs B, et al. Milk thistle: effects on liver disease and cirrhosis and clinical adverse effects. Evid Rep Technol Assess (Summ) 2000;(21):1-3.
  10. Pares A, Planas R, Torres M, et al. Effects of silymarin in alcoholic patients with cirrhosis of the liver: results of a controlled, double-blind, randomized and multicenter trial. J Hepatol 1998;28(4):615-621.
  11. Singh RP, Agarwal R. Prostate cancer prevention by silibinin. Curr Cancer Drug Targets 2004 Feb;4(1):1-11.
  12. Velussi M, Cernigoi AM, De Monte A, et al. Long-term (12 months) treatment with an anti-oxidant drug (silymarin) is effective on hyperinsulinemia, exogenous insulin need and malondialdehyde levels in cirrhotic diabetic patients. J Hepatol 1997;26(4):871-879.
  13. Zuber R, Modriansky M, Dvorak Z, et al. Effect of silybin and its congeners on human liver microsomal cytochrome P450 activities. Phytother Res 2002;Nov, 16(7):632-638.

Last updated July 14, 2005