Milk thistle (Silybum marianum) has been used since Greco-Roman times
as an herbal remedy for a variety of ailments, particularly liver problems. In
the late 19th and early 20th centuries physicians in the United States used milk
thistle seeds to relieve congestion of the liver, spleen, and kidneys. Today,
several scientific studies suggest that active substances in milk thistle
(particularly silymarin) protect the liver from damage caused by viruses,
toxins, alcohol, and certain drugs such as acetaminophen (a common over the
counter medication used for headaches and pain; acetaminophen, also called
paracetamol, can cause liver damage if taken in large quantities or by people
who drink alcohol regularly.)
Many professional herbalists recommend milk thistle extract for the
prevention and/or treatment of various liver disorders including viral
hepatitis, fatty liver associated with long term alcohol use, and liver damage
from drugs and industrial toxins such as carbon tetrachloride.
Mushroom Poisoning Milk thistle has also been used as a
preventive and/or antidote to poisoning by deathcap mushroom (Amanita
phalloides). Animal studies have found that milk thistle extract completely
counteracts the toxic effects of the mushroom when given within 10 minutes of
ingestion. If given within 24 hours of ingestion, the herb significantly reduces
the risk of liver damage and death.
Liver disease from alcohol A comprehensive review by the U.S.
Agency for Healthcare Research and Quality (AHRQ) recently identified 16
scientific studies on the use of milk thistle for the treatment of various forms
of liver disease. A European standardized extract of milk thistle was used in
most of the trials.
Problems in study design (such as small numbers of participants, variations
in the causes of liver disease, and differences in dosing and duration of milk
thistle therapy) made it difficult to draw any definitive conclusions. However,
five of seven studies evaluating milk thistle for alcoholic liver disease found
significant improvements in liver function. Those with the mildest form of the
disease appeared to improve the most. Milk thistle was less effective for those
with severe liver disease such as cirrhosis. Cirrhosis is characterized by
scarring and permanent, non-reversible damage to the liver. It is often referred
to as end-stage liver disease.
Viral hepatitis Despite the fact that milk thistle is widely
used in the treatment of hepatitis (particularly hepatitis C), results from four
viral hepatitis studies were contradictory. Some found improvements in liver
enzyme activity while others failed to detect these benefits. None of the
studies compared milk thistle with interferon or other medications for viral
Cancer Preliminary laboratory studies also suggest that active
substances in milk thistle may have anti-cancer effects. One active substance
known as silymarin has strong antioxidant properties and has been shown to
inhibit the growth of human prostate, breast, and cervical cancer cells in test
tubes. Further studies are needed to determine whether milk thistle is safe or
effective for people with these forms of cancer.
High cholesterol One animal study found that silymarin (an
active compound in milk thistle) worked as effectively as the
cholesterol-lowering drug probucol, with the additional benefit of substantially
increasing HDL ("good") cholesterol. Further studies in people are
Milk thistle is native to the Mediterranean, but is now widespread throughout
the world. This stout thistle usually grows in dry, sunny areas. The stem
branches at the top, and reaches a height of 4 to 10 feet. The leaves are wide,
with white blotches or veins. The flowers are red-purple. The small,
hard-skinned fruit is brown, spotted, and shiny. Milk thistle is easy to grow,
and it matures quickly, in less than a year.
What's It Made Of?
The active ingredient, or liver-protecting compound in milk thistle is known
as silymarin. This substance, which actually consists of a group of compounds
called flavonolignands, helps repair liver cells damaged by alcohol and other
toxic substances. Silymarin also keeps new liver cells from being destroyed by
these same substances, reduces inflammation (important for people with liver
inflammation or hepatitis), and has potent antioxidant effects.
Most milk thistle products are standardized preparations extracted from the
fruits (seeds) of the plant. Most preparations are standardized to contain 70%
to 80% of flavonolignans (silibinin, silychristin, and silydianin), collectively
known as silymarin.
Capsules of standardized dried herb (each capsule contains about 120
to 140 mg silymarin)
Silymarin phosphatidyl choline complex
The silymarin in milk thistle seeds is difficult to absorb. The more
concentrated the solution of silymarin, the more easily it is absorbed and the
more readily it enters the bloodstream. Standardized capsules are the most
concentrated form and, therefore, should be used whenever possible.
Silymarin-phosphatidylcholine complex may be absorbed even more easily than
regular standardized milk thistle. In clinical trials, the
silymarin-phosphatidylcholine complex has worked better than silymarin by itself
for treating liver disorders. A key element in cell membranes,
phosphatidylcholine helps the silymarin attach easily to the cell membranes.
This may keep toxins from getting inside liver cells. Alcohol extracts may be
less effective and, therefore, should likely be avoided.
How to Take It
Adjust the recommended adult dose to account for the child's weight. Most
herbal dosages for adults are calculated on the basis of a 150 lb (70 kg) adult.
Therefore, if the child weighs 50 lb (20 to 25 kg), the appropriate dose of milk
thistle for this child would be 1/3 of the adult dosage.
Recommended dose: Generally 12 to 15 g dried herb (200 to 400 mg
silymarin) per day or silymarin-phosphatidylcholine complex 100 to 200 mg two
times per day.
For liver protection: 120 mg silymarin (about 2 capsules), two times
To treat liver damage (from alcohol, drugs, or chemicals): 120 mg
(about 3 capsules), three times per day
The use of herbs is a time-honored approach to strengthening the body and
treating disease. Herbs, however, contain active substances that can trigger
side effects and interact with other herbs, supplements, or medications. For
these reasons, herbs should be taken with care, under the supervision of a
practitioner knowledgeable in the field of botanical medicine.
Side effects from milk thistle happen only rarely, but may include stomach
pain, nausea, vomiting, diarrhea, headache, rash or other skin reactions, joint
pain, impotence, and anaphylaxis (a life-threatening allergic reaction that
causes throat tightness, shortness of breath, and, possibly, loss of
consciousness.) The last two reactions listed are extremely rare.
Milk thistle should not be used by pregnant or breastfeeding
If you are currently being treated with any of the following medications, you
should not use milk thistle without first talking to your healthcare
Similar to its ability to protect against damage to the liver from alcohol
and acetominophen, as discussed in the Overview, milk thistle may also protect
against liver damage from the following medications:
Antipsychotics: This group of medications used for
schizophrenia includes butyrophenones (such as haloperidol) and phenothiazines
(such as chlorpromazine, fluphenazine, and promethazine)
Phenytoin: a medication used for seizures
Halothane: a medication used during general anesthesia
Other medications that may interact with milk thistle include:
Aspirin One animal study found that milk thistle may enhance
the effectiveness of aspirin in rats with liver cirrhosis. Whether this
herb-drug combination has the same effect in people is not known at this
Chemotherapy medications Preliminary research suggests that
silybin may enhance the tumor fighting effects of cisplatin and doxorubicin when
tested against breast and ovarian cancer cells.
In addition, milk thistle may protect the kidneys against toxic side effects
associated with cisplatin and cyclosporine, two medications that are commonly
used to treat cancer.
On the other hand, a different laboratory study revealed that the anticancer
effect of cisplatin and ifosfamide was diminished in the presence of milk
thistle. More research needs to be done to assess how milk thistle and
cancer-fighting agents interact.
Agency for Healthcare Research and Quality. Milk thistle: effects on liver
disease and cirrhosis and clinical adverse effects. Summary, evidence
report/technology assessment: number 21, September 2000. Accessed at:
on April 15, 2002.
Bhatia N, Zhao J, Wolf DM, Agarwal R. Inhibition of human carcinoma cell
growth and DNA synthesis by silibinin, an active constituent of milk thistle:
comparison with silymarin. Cancer Lett. 1999;147(1-2):77-84.
Blumenthal M, Goldberg A, Brinckmann J. Herbal Medicine: Expanded
Commission E Monographs. Newton, MA: Integrative Medicine Communications;
Bokemeyer C, Fels LM, DunnT, et al. Silibinin protects against
cisplatin-induced nephrotoxicity without compromising cisplatin on isosfamide
anti-tumor activity. Br J Cancer.
Brinker F. Herb Contraindications and Drug Interactions. 2nd ed.
Sandy, OR: Eclectic Medical Publications; 1998:103-104.
Campos R, Garrido A, Guerra R, et al. Silybin dihemisuccinate protects
against glutathione depletion and lipid peroxidation induced by acetaminophen on
rat liver. Planta Med. 1989;55:417-419.
Feher J, Deak G, Muzes G, Lang I, Neiderland V, Nekan K, et al.
Hepatoprotective activity of silymarin therapy in patients with chronic
alcoholic liver disease. Orv Hetil. 1990;130:51.
Ferenci P, Dragosics B, Dittrich H, Frank H., Benda L, Lochs H, et al.
Randomized controlled trial of silymarin treatment in patients with cirrhosis of
the liver. J Hepatol. 1989;9:105-113.
Fintelmann V. Modern phytotherapy and its uses in gastrointestinal
conditions. [Review]. Planta Med. 1991;57(7):S48-52.
Flora K, Hahn M, Rosen H, Benner K. Milk thistle (Silybum marianum)
for the therapy of liver disease. Am J Gastroenterol.
Gaedeke J, Fels LM, Bokemeyer C, et al. Cisplatin nephrotoxicity and
protection by silibinin. Nephrol Dial Transplant.
Giese LA. A study of alternative health care use for gastrointestinal
disorders. Gastroenterol Nurs. 2000;23(1):19-27.
Jiang C, Agarwal R, Lu J. Anti-angiogenic potential of a cancer
chemopreventive flavonoid antioxidant, Silymairn: inhibition of key attributes
of vascular endothelial cells and angiogenic cytokine secretion by cancer
epithelial cells. Biochem Biophys Res Commun. 2000;276:371-378.
Krecman V, Skottova N, Walterova D, Ulrichova J, Simanek V. Silymarin
inhibits the development of diet-induced hypercholesterolemia in rats. Planta
Low Dog T. Traditional and alternative therapies for breast cancer. Altern
Ther Health Med. 2001;7(3):36-47.
Luper S. A review of plants used in the treatment of liver disease: part 1.
[Review]. Altern Med Rev. 1998;3(6):410-421.
Mourelle M, Favari L. Silymarin improves metabolism and disposition of
aspirin in cirrhotic rats. Life Sci.
Palasciano G, Portincasa P, Palmieri V, Ciani D, Vendemiale G, Altomare E.
The effect of silymarin on plasma levels of malon-dialdehyde in patients
receiving long-term treatment with psychotropic drugs. Curr Therapeut
Rotblatt M, Ziment I. Evidence-Based Herbal Medicine. Philadelphia,
PA: Hanley & Belfus, Inc; 2002:266-271.
Scanbia G, De Vincenzo RD, Ranelletti FO, et al. Antiproliferative effect of
Silybin on gynaecological malignancies: synergism with cisplatin an doxorubicin.
Eur J Cancer. 1996;32A(5):877-882.
Silybum marianum (Milk Thistle). Alt Med Rev.
Valenzuela A, Lagos C, Schmidt K, et al. Silymarin protection against hepatic
lipid peroxidation induced by acute ethanol intoxication in the rat. Biochem
von Schonfeld J, Weisbrod B, Muller MK. Silibinin, a plant extract with
antioxidant and membrane stabilizing properties, protects exocrine pancreas from
cyclosporin A toxicity. Cell Mol Life Sci.
White L, Mavor S. Kids, Herbs, Health. Loveland, Colo: Interweave
Press; 1998:22, 36.
Zi X, Feyes DK, Agarwal R. Anticarcinogenic effect of a flavonoid
antioxidant, silymarin, in human breast cancer cells MDA-MB 468: induction of G1
arrest through an increase in Cip1/p21 concomitant with a decrease in kinase
activity of cyclin-dependent kinases and associated cyclins.
Clin Cancer Res. 1998;4(4):1055-1064.
Zi X, Mukhtar H, Agarwal R. Novel cancer chemopreventive effects of a
flavonoid antioxidant silymarin: inhibition of mRNA expression of an endogenous
tumor promoter TNF-alpha. Biochem Biophys Res Commun.
Review Date: April 2002
Reviewed By: Participants in the review process include: Jacqueline A. Hart, MD,
Department of Internal Medicine, Newton-Wellesley Hospital, Harvard University
and Senior Medical Editor Integrative Medicine, Boston, MA; Gary Kracoff, RPh
(Pediatric Dosing section February 2001), Johnson Drugs, Natick, MA; Steven
Ottariono, RPh, Veteran's Administrative Hospital, Londonderry, NH; David
Winston, Herbalist (April 1999), Herbalist and Alchemist, Inc., Washington, NJ;
Tom Wolfe, P.AHG (April 1999), Smile Herb Shop, College Park, MD. All
interaction sections have also been reviewed by a team of experts including
Joseph Lamb, MD (July 2000), The Integrative Medicine Works, Alexandria,
VA;Enrico Liva, ND, RPh (August 2000), Vital Nutrients, Middletown, CT; Brian T
Sanderoff, PD, BS in Pharmacy (March 2000), Clinical Assistant Professor,
University of Maryland School of Pharmacy; President, Your Prescription for
Health, Owings Mills, MD; R. Lynn Shumake, PD (March 2000), Director,
Alternative Medicine Apothecary, Blue Mountain Apothecary & Healing Arts,
University of Maryland Medical Center, Glenwood, MD; Ira Zunin, MD, MPH, MBA
(July 2000), President and Chairman, Hawaii State Consortium for Integrative
Medicine, Honolulu, HI.
The publisher does not accept any responsibility for the accuracy of
the information or the consequences arising from the application, use, or misuse
of any of the information contained herein, including any injury and/or damage
to any person or property as a matter of product liability, negligence, or
otherwise. No warranty, expressed or implied, is made in regard to the contents
of this material. No claims or endorsements are made for any drugs or compounds
currently marketed or in investigative use. This material is not intended as a
guide to self-medication. The reader is advised to discuss the information
provided here with a doctor, pharmacist, nurse, or other authorized healthcare
practitioner and to check product information (including package inserts)
regarding dosage, precautions, warnings, interactions, and contraindications
before administering any drug, herb, or supplement discussed