Supplement Forms/Alternate Names:

  • Silymarin, silybum marianum, Mary thistle, holy thistle


Milk thistle is a spiky green plant. Silymarin is a compound found in its seeds. It has been used to lower cholesterol and improve liver function. Milk thistle can be taken as a pill, powder, or extract. It can also be applied as a cream.


150 milligrams 2 to 3 times daily

What Research Shows

Likely Effective

May Be Effective

May Not Be Effective

  • Nonalcoholic steatohepatitis—may not ease symptoms G1

Not Enough Data to Assess

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Safety Notes

It is likely safe to take milk thistle and to use it on the skin for a short time. Not enough studies have been done to say whether it is safe to use for a long period or by women who are pregnant or breastfeeding. H3


Talk to your doctor about any supplements or therapy you would like to use. Some can interfere with treatment or make conditions worse, such as:

  • People taking antibiotics should talk to their doctor before taking milk thistle. It may make the medicine less effective. H4
  • People taking blood thinners should talk to their doctor before taking milk thistle. It may increase the risk of bleeding. H2
  • People taking antiretroviral medicine should talk to their doctor before taking milk thistle. It may interact with the medicine. H1


REFA Acute Hepatitis

REFA1 El-Kamary SS, Shardell MD, et al. A randomized controlled trial to assess the safety and efficacy of silymarin on symptoms, signs and biomarkers of acute hepatitis. Phytomedicine. 2009;16(5):391-400.

REFB Breastfeeding Support

REFB1 Mortel M, Mehta SD. Systematic review of the efficacy of herbal galactogogues. J Hum Lact. 2013 May;29(2):154-162.

REFB2 Zecca E, Zuppa AA, et al. Efficacy of a galactogogue containing silymarin-phosphatidylserine and galega in mothers of preterm infants: a randomized controlled trial. Eur J Clin Nutr. 2016 Oct;70(10):1151-1154.

REFB3 Serrao F, Corsello M, et al. The Long-Term Efficacy of a Galactagogue Containing Sylimarin-Phosphatidylserine and Galega on Milk Production of Mothers of Preterm Infants. Breastfeed Med. 2018 Jan/Feb;13(1):67-69.

REFC Decompensated Liver Cirrhosis

REFC1 May be improve quality of life. Fathalah WF, Abdel Aziz MA, Abou El Soud NH, El Raziky MES. High Dose of Silymarin in Patients with Decompensated Liver Disease: A Randomized Controlled Trial. J Interferon Cytokine Res. 2017 Nov;37(11):480-487.

REFD Diabetes

REFD1 Sulksomboon N, Poolsup N, et al. Meta-analysis of the effect of herbal supplement on glycemic control in type 2 diabetes. J Ethnopharmacol. 2011;137(3):1328-1333.

REFD2 Derosa G, D’Angelo A, et al. The role of a fixed Berberis aristata/Silybum marianum combination in the treatment of type 1 diabetes mellitus. Clin Nutr. 2016;33(5):1091-1095.

REFD3 Voroneanu L, Nistor I, et al. Silymarin in Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. J Diabetes Res. 2016;2016:5147468.

REFD4 Voroneanu L, Siriopol D, et al. Addition of silymarin to renin-angiotensin system blockers in normotensive patients with type 2 diabetes mellitus and proteinuria: a prospective randomized trial. Int Urol Nephrol. 2017 Dec;49(12):2195-2204.

REFD5 Ebrahimpour-Koujan S, Gargari BP, et al. Lower glycemic indices and lipid profile among type 2 diabetes mellitus patients who received novel dose of Silybum marianum (L.) Gaertn. (silymarin) extract supplement: A Triple-blinded randomized controlled clinical trial. Phytomedicine. 2018 May 15;44:39-44.

REFD6 Hadi A, Pourmasoumi M, et al. The effects of silymarin supplementation on metabolic status and oxidative stress in patients with type 2 diabetes mellitus: A systematic review and meta-analysis of clinical trials. Complement Ther Med. 2018 Dec;41:311-319.

REFE Dyslipidemia

REFE1 Derosa G, Bonaventura A, et al. Berberis aristata/Silybum marianum fixed combination on lipid profile and insulin secretion in dyslipidemic patients. Expert Opin Biol Ther. 2013;13(11):1495-1506.

REFE2 Derosa G, Bonaventura A, et al. Effects of Berberis aristata/Silybum marianum association on metabolic parameters and adipocytokines in overweight dyslipidemic patients. J Biol Regul Homeost Agents. 2013;27(3):717-728.

REFE3 Derosa G, Romano D, et al. Berberis aristata/Silybum marianum fixed combination (Berberol(®)) effects on lipid profile in dyslipidemic patients intolerant to statins at high dosages: a randomized, placebo-controlled, clinical trial. Phytomedicine. 2015 Feb 15;22(2):231-237.

REFF Inflammatory Bowel Disease

REFF1 Langhorst J, Wulfert H, et al. Systematic review of complementary and alternative medicine treatments in inflammatory bowel diseases. J Crohns Colitis. 2015 Jan;9(1):86-106. doi: 10.1093/ecco-jcc/jju007. Epub 2014 Nov 28. Review. PubMed PMID: 25518050.

REFG Nonalcoholic Steatohepatitis

REFG1 Wah Kheong C, Nik Mustapha NR, et al. A Randomized Trial of Silymarin for the Treatment of Nonalcoholic Steatohepatitis. Clin Gastroenterol Hepatol. 2017 Dec;15(12):1940-1949.e8.

REFH Safety

REFH1 Jalloh MA, Gregory PJ, et al. Dietary supplement interactions with antiretrovirals: a systematic review. Int J STD AIDS. 2017 Jan;28(1):4-15.

REFH2 Asher GN, Corbett AH, et al. Common Herbal Dietary Supplement-Drug Interactions. Am Fam Physician. 2017 Jul 15;96(2):101-107.

REFH3 Han Y, Guo D, et al. Effect of silymarin on the pharmacokinetics of losartan and its active metabolite E-3174 in healthy Chinese volunteers. Eur J Clin Pharmacol. 2009 Jun;65(6):585-591.

REFH4 Izzo AA. Interactions between herbs and conventional drugs: overview of the clinical data. Med Princ Pract. 2012;21(5):404-28. doi: 10.1159/000334488. Epub 2012 Jan 11. Review. PubMed PMID: 22236736.

REFI Trichotillomania

REFI1 refI1Grant JE, Redden SA, et al. Milk Thistle Treatment for Children and Adults with Trichotillomania: A Double-Blind, Placebo-Controlled, Crossover Negative Study. J Clin Psychopharmacol. 2019 Mar/Apr;39(2):129-134.

REFJ Ulcerative Colitis

REFJ1 Rastegarpanah M, Malekzadeh R, et al. A randomized, double blinded, placebo-controlled clinical trial of silymarin in ulcerative colitis. Chin J Integr Med. 2015 Dec;21(12):902-6.

Revision Information

  • Reviewer: EBSCO NAT Review Board Eric Hurwitz, DC
  • Review Date: 03/2020
  • Update Date: 06/29/2020