Milk Thistle (Silybum marianum)


Milk Thistle Overview:

Milk thistle originated from the Mediterranean. It is most useful for treating liver dysfunctions and promoting lactation in females (hence the name).

This thorny herb contains a series of bitter-tasting chemicals that work to stimulate the production of bile in the liver and the release of bile into the duodenum. They also upregulate both phase 1 and phase 2 liver detoxification which then leads to its long list of beneficial actions on the health of the liver, and metabolism. This includes fatty liver disease, diabetes, high cholesterol, and drug or mycotoxin metabolism and excretion.

Milk thistle is currently the best-known antidote for Amanita muscarina (fly agaric) poisoning.

+ Indications:

  • Amanita muscaria mushroom poisoning
  • Anorexia nervosa
  • Cancer topical use
  • Chemotherapy supportive agent
  • Chronic fatigue syndrome
  • Chronic liver disease
  • Chronic uterine problems
  • Cirrhosis
  • Constipation
  • Dyspepsia
  • Endometriosis
  • Fatty liver
  • Gallbladder dysfunctions
  • Gastrointestinal pain and discomfort
  • Improve liver detoxification
  • Jaundice
  • Liver conditions
  • Metabolic syndrome
  • Multiple sclerosis
  • Nausea during pregnancy
  • Nephroprotective and hepatoprotective
  • Poor milk production
  • Psoriasis
  • Radiation damage in the liver
  • Substance Abuse
  • Toxicity due to environmental chemicals and drugs
  • Viral Hepatitis
  • Weak digestion

+ Contraindications:

None reported.

Herbal Actions:

  • Hepatoprotective
  • hepatotrophorestorative
  • Antioxidant
  • Choleretic
  • Cholagogue
  • Mild hypocholesterolemic
  • Galactagogue
  • Nephroprotective
  • Demulcent
  • Anti-inflammatory
  • Antiviral

What is Milk Thistle Used For?

Milk thistle is mainly used as a liver tonic for those with metabolic conditions, weak digestion, or high cholesterol. It is also used in acute conditions for dyspepsia, upset stomach, indigestion, or liver toxicity to certain drugs or mycotoxins. In females, milk thistle is popular for stimulating the flow of milk for nursing mothers.

Other conditions related to secondary effects of poor liver health such as eczema, psoriasis, jaundice, and anorexia are also commonly treated with milk thistle.


Traditional Uses:

Milk thistle has been reportedly used since the 4th century BCE [4].

This herb was used in much the same way that blessed thistle (Carbenia benedicta) was used. This involved its use as a supplement for nursing mothers [6].

In Europe, milk thistle was used as a liver tonic [1, 9, 18], and Gerard suggested that milk thistle is the best remedy for all melancholy diseases. This was a way of suggesting its benefits on the liver [6]. This is probably the use of milk thistle is most famous for, and has been backed up by modern evidence-based medicine [1]. In 19th century Germany, its use for jaundice, hepatic, hepatitis, and hemorrhoids [5] boosted the popularity of this herb to its virtual superstar status currently as a biliary and hepatoprotective herb.

Dioscorides suggested its use against snake bites (the seeds), even in children. Some of its old folk use derived from the Saxons suggests it to fend off snakes if worn around the neck [6].

Culpepper suggested milk thistle to be useful for curing and preventing infection during the plague, as well as to remove obstructions from the liver and spleen [6].

One of the most common traditional uses of this herb is to remove the prickles of young plants, boil, and consume as a spring blood cleanser [5, 6].


Milk Thistle Monograph

Part Used

Seeds, root, and leaves (mostly the seeds).

Family Name



The Mediterranean
Australia (invasive)
Throughout Europe

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Constituents of Interest

  • Silymarin

Common Names

  • Milk Thistle
  • St. Mary's Thistle
  • Marian Thistle
  • Our Lady's Thistle
  • Carduus Marianus

Botanical Information:

Milk Thistle is part of the Asteraceae family of plants, which is the largest family of flowering plants in the world. It is a thistle, which places it in the Cynareae tribe. Other members of this tribe includes artichoke, cotton thistle, and the common thistle.


Habitat Ecology, & Distribution:

Milk thistle is native to the Mediteranean, but has spread the world over. In some countries, such as Australia this herb is considered a noxious weed [5].


Harvesting Collection, & Preparation:

Silymarin is not water soluble and is therefore ineffective as a tea. The best extracts are suggested to be in a standardised extract withg 70% to 80% silymarin [3].


Pharmacology & Medical Research

+ Hepatoprotective

Milk thistle seed extract has been shown to improve liver function that has been impaired by viral infections such as hepatitis, exposure to toxins, solvents, and acetaminophen [2].

The flavone and flavonolignan components are suggested to provide most of the hepatoprotective effects, the most studied of which is the complex known as silymarin [1], which is reportedly not found in the leaves but only in the seed [3].

Silybum marianum has been found to offer protective benefit against substances including carbon tetrachloride, ethanol, paracetamol-induced liver peroxidation cyclosporin, phenothiazine, a butyrophenone, erythromycin, amitriptyline and nortriptyline oestradiol, Amanita phalloides, tacrine, Iron overload [3].

Aactions associated with hepatoprotective actions of milk thistle include:

  1. Antioxidant activity through free radical scavenging, the intracellular concentration of glutathione, reduced lipid peroxidation and increased catalase activity [5, 11].
  2. Enhanced synthesis of RNA and subsequent cellular regeneration [5]
  3. Antifibrotic actions through NF-kB inhibition and hepatic stellate cell activation [5, 7, 11, 16, 17].
  4. Toxin blockade through modulation of the mitochondrial membrane [3, 5].
  5. Anti-inflammatory action through inhibition of TN-F alpha expression, and nitric oxide inhibition [5, 12-15].
  6. Competitive inhibition of phalloidin-transporting system [5].
  7. Glucose and lipid metabolism improvement [5]



The silymarin absorption rate varies between 20% and 50% in humans. It's absorbed in the small intestine and peaks in the blood 2 hours after taking orally. The half-life is around 6 hours. 5-7% of what is absorbed gets excreted by the kidneys, most, however, is absorbed by the liver and is incorporated into bile. Here it then undergoes phase I and phase II metabolism. [3].

Chemical Breakdown:

Flavolignans 1.5-3%

  • Silymarin. (Complex of at least seven flavolignans)
    • Most biologically significant of this group appears to be Silybin (A, and B)
    • Silydianin
    • Silychristin
    • Silymandin
    • Isosilybin A and B


  • Quercetin
  • Taxifolin
  • Dehydrokaempferol

Lipids 20–30%

  • Linoleic acid
  • Oleic acid (30%)
  • Palmitic acid (6%)


  • Cholesterol
  • Campesterol
  • Stigmasterol
  • Sitosterol


Still compiling research


  • Arabinose
  • Rhamnose
  • Xylose
  • Glucose


Still compiling research


Still compiling research.


Clinical Applications Of Milk Thistle:

Milk thistle has undergone a lot of research for its actions on the liver. The ability for milk thistle to increase glutathione free radical scavenging, enhance cellular regeneration of liver tissue, inhibit fibrosis of the liver, reduce inflammation through TNF and NF-kB modulation, inhibition of phalloidin transporting system, and upregulation of both phase 1 and phase 2 liver detox pathways allows milk thistle to exert a broad protective effect on the liver and related systems.

Milk thistle's ability to improve overall liver health makes it useful for liver specific conditions like alcoholic liver disease, cirrhosis, hepatitis, and liver toxicity due to drug or mycotoxin intake. Additionally, these effects can reach to other areas of health affected by the liver such as high cholesterol, diabetes, atherosclerosis, and hypertriglyceridemia. Milk thistle can be highly beneficial for some of the most common chronic conditions we see today through its ability to regulate and improve the general health of the liver.

Milk thistles ability to improve liver health, and its bitter properties allow it to provide benefit for conditions involving poor bile release or production, resulting in symptoms like indigestion, anorexia, and flatulence or bloating.

Milk thistle is also a reliable herb for improving the flow of milk in new mothers.



Due to the ability for milk thistle to upregulate liver detoxifiication, it may increase the onset or potency of prodrug medications like codeine, and decrease the effectiveness of drugs metabolised by the liver. Caution is advised if taking any medications.



  • Lecithin enhances the absorption of silymarin (in vivo)
  • Seeds, e.g. fennel, caraway in inadequate milk production
  • Cynara – liver damage, disease, hypercholesteraemia


Justin Cooke, BHSc

The Sunlight Experiment

(Updated May 2019)


Recent Blog Posts:


  1. Hoffmann, D. (2003). Medical herbalism: The science and practice of herbal medicine. Rochester, VT: Healing Arts Press. (Pg. 584)

  2. McCaleb R, Leigh E, Morien K. (1999). The encyclopedia of popular herbs. Roseville, CA: Prima health.

  3. Powers J. (2014). Silybum marianum Monograph. JATMS. Vol 20(1).

  4. DerMarderosian A, Beutler JA. (2010). The review of natural products: the most complete source of natural product information. 6th ed. St. Louis, Mo.: Wolters Kluwer Health : Facts and Comparisons.

  5. Bone K, Mills S. (2013). Principles and Practice of Phytotherapy. Elsevier health. China. (Pg. 861-882)

  6. A Modern Herbal. (1931). Thistle (Milk). Retrieved from

  7. Loguercio C, Feste D. (2011). Silybin and the liver: From basic research to clinical practice. World Journal of Gastroenterolgy. 17(18):2288–301.

  8. The Sunlight Experiment. (2016). Artichoke — The Sunlight Experiment. Retrieved July 22, 2016, from

  9. Rambaldi A, Jacobs BP, Iaquinto G, Gluud C. (2005). Milk thistle for alcoholic and/or hepatitis B or C liver diseases--a systematic cochrane hepato-biliary group review with meta-analyses of randomized clinical trials. Am J Gastroenterol. 100:2583–2591.

  10. Morishima C, Shuhart MC, Wang CC, et al. (2010). Silymarin Inhibits In Vitro T-Cell Proliferation and Cytokine Production in Hepatitis C Virus Infection. Gastroenterology. 138:671–681.

  11. Trappoliere M, Caligiuri A, Schmid M, et al. (2009). Silybin, a component of sylimarin, exerts anti-inflammatory and anti-fibrogenic effects on human hepatic stellate cells. J Hepatol. 50:1102–1111.

  12. Polyak SJ, Morishima C, Shuhart MC, et al. (2007). Inhibition of T-cell inflammatory cytokines, hepatocyte NF-kappaB signaling, and HCV infection by standardized Silymarin. Gastroenterology. 132:1925–1936.

  13. Ahmed-Belkacem A, Ahnou N, Barbotte L. (2009). Silibinin and Related Compounds Are DirectInhibitors of Hepatitis C Virus RNA-Dependent RNA Polymerase. Gastroenterology.

  14. Bonifaz V, Shan Y, Lambrecht RW (2009). Effects of silymarin on hepatitis C virus and haemoxygenase-1 gene expression in human hepatoma cells. Liver Int. 29:366–373.

  15. Ferenci P, Scherzer TM, Kerschner H, et al. (2008). Silibinin is a potent antiviral agent in patients with chronic hepatitis C not responding to pegylated interferon/ribavirin therapy. Gastroenterology. 135:1561–1567.

  16. Boigk G, Stroedter L, Herbst H, et al. (1997). Silymarin retards collagen accumulation in early and advanced biliary fibrosis secondary to complete bile duct obliteration in rats. Hepatology. 26:643–649.

  17. Dehmlow C, Erhard J, de GH. (1996). Inhibition of Kupffer cell functions as an explanation for the hepatoprotective properties of silibinin. Hepatology. 1996; 23:749–754.

  18. Mayer KE, Myers RP, Lee SS. (2005). Silymarin treatment of viral hepatitis: a systematic review. J Viral Hepat. 12:559–567.