Milk Thistle Summary:

Milk thistle is a thorny herb, which is highly esteemed for its medicinal actions on promoting healthy milk production. Milk thistle also has a potent action on the liver, providing powerful hepatoprotective, detoxificant, and choleretic (bile secreting) effects.

Milk thistle directly improves the elimination of toxins like nicotine and alcohol, as well as muscarines (from poisonous mushrooms), and aspirin. It is a premier liver tonic and medicine. Higher doses are used to treat liver conditions, while lower doses make for an effective liver tonic taken over long periods of time. 


Botanical Name

Silybum marianum

Former: Carduus marianus



Part Used

Seed (fruit), root, leaves
The seeds are mostly used as medicine

Herbal Actions:

  • Hepatoprotective [1-3, 5, 7 11, 16, 17]
  • hepatotrophorestorative [5]
  • Antioxidant
  • Choleretic
  • Cholagogue
  • Mild hypocholesterolemic
  • Galactagogue
  • Nephroprotective
  • Demulcent
  • Anti-inflammatory [5, 10-12]
  • Antiviral [12-15]
milk thistle flower heads


Liquid Extract (1:1)

4-9 ml/day


600-900 mg/day
Concentrated extract standardized to 60-70% silymarin (140 mg silymarin per 200 mg capsle or tablet).

Seed (oral)

4-9 g/day

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Digestive System Disorders

  • Dyspepsia
  • Poor digestion
  • Gastrointestinal pain and discomfort

Liver Conditions

  • Toxicity due to environmental chemicals and drugs
  • Amanita muscaria mushroom poisoning
  • Chronic liver disease
  • Radiation damage in the liver
  • Viral hepatitis
  • Cirrhosis
  • Improve detoxification and reduce damage caused during this process
  • Jaundice
  • Gallbladder dysfunctions
  • Alcoholic and non-alcoholic liver damage
  • Fatty liver

Other Conditions

  • Poor milk production
  • Nausea during pregnancy
  • Chemotherapy supportive agent
  • Nephroprotective and hepatoprotective
  • Cancer (topical use)
  • Anorexia nervosa
  • Chronic uterine problems
  • Psoriasis


  • Caution advised with drug interactions through the CYP 450 enzymes

Common Names:

Milk Thistle

St Mary's Thistle

marian Thistle

Our Lady's Thistle

Carduus marianus


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 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 haemorrhoids [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 ward 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].   

    Botanical Description:

    This annual (or biennial) plant can grow up to 2 m tall.  It is a member of the Asteraceae family, and is in the same tribe as globe artichoke (Cynara scolymus) [5], which is another useful hepatic herb [8]. 

    Habitat Ecology, and 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, and 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]. 


    [1, 5, 6]. 

    + Flavolignans 1.5-3%

    • Silymarin. (Complex of at least 7 flavolignans)
      • Most biologically significant of this group appears to be Silybin (A, and B)
      • Silydianin
      • Silychristin
      • Silymandin
      • Isosilybin A and B

    + Flavonoids

    • Quercetin
    • Taxifolin
    • Dehydrokaempferol

    + Lipids 20–30%

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

    + Sterols

    • Cholesterol
    • Campesterol
    • Stigmasterol
    • Sitosterol

    + Mucilages

    Still compiling research

    + Sugars

    • Arabinose
    • Rhamnose
    • Xylose
    • Glucose

    + Amines

    Still compiling research

    + Saponins

    Still compiling research.

    The silymarin absorption rate varies between 20% and 50% in humans. As it becomes 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].    

    Pharmacology and Medical Research:

    + Hepatoprotective | Hepatotrophorestorative

    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 flavolignan 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, butyrophenone, erythromycin, amitriptyline and nortriptyline oestradiol, Amantia phalloides, tacrine, Iron overload [3].

    Currently, the actions associated with milk thistles hepatoprotective actions are:

    1. Antioxidant activity through free radical scavenging, intracellular concentration of glutathione, reduced lipid peroxidation, and increased catylase 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]



    David Hoffmann Suggests milk thistle has no reported side effects or drug interactions [1].  



    Consider the actions on the p-450 enzymes of the liver. if taking drugs to stimulate or inhibit this pathway, caution should be used. also be cautions when using this herb with drugs that are metabolized through this pathway, as taking this herb in combination may inhibit their removal, or speed the metabolism too much to be effective. 



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


    Justin Cooke

    The Sunlight Experiment

    Updated: June 2017

    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.
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    6. A Modern Herbal. (1931). Thistle (Milk). Retrieved from
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    8. The Sunlight Experiment. (2016). Artichoke — The Sunlight Experiment. Retrieved July 22, 2016, from
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    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.