# Milk thistle (Silybum marianum) *St Mary’s thistle, Marian thistle; the *silubon* of Dioscorides; *Carduus marianus* L.; *Silybum marianum* (L.) Gaertn.; in pharmacy *Silybi mariani fructus** **Known today as.** *Silybum marianum*, an annual or biennial thistle of the family Asteraceae, native to Europe, Asia Minor, and North Africa by LiverTox’s account. What pharmacy calls the seed is technically the fruit, and it is the part used; from it comes silymarin, the mixture of flavonolignans, silibinin chief among them, on which modern interest rests. Kind: Plant > **Caution.** Not for those allergic to plants of the Asteraceae (Compositae) family, nor recommended under eighteen. The European agency advises seeing a doctor at once if jaundice or a change in the colour of urine or stool appears. Mild stomach upsets, headache, and allergic reactions, anaphylaxis among them, have been reported. LiverTox rates it an unlikely cause of liver injury; it “has not been implicated in causing liver injury,” and there is little evidence of clinically significant interactions with other drugs. ## What was it used for? A food and a liver medicine. Dioscorides knew it as a pot-herb, the young shoots boiled with oil and salt, and its root juice as an emetic. The assessment report of the European Medicines Agency, following the Commission E monograph, records that the leaves were used for a variety of ailments, particularly of the liver, since Greco-Roman times, that American Eclectic physicians of the late nineteenth and early twentieth centuries valued the seeds for congestion of the liver, spleen, and kidneys, and that in Germany it was widely used for “chronic hepatitis of all types.” ## What does modern science say? The European Medicines Agency’s herbal committee accepts the fruit as a traditional herbal medicine, “exclusively based upon long-standing use,” for the symptomatic relief of digestive disorders, fullness, and indigestion and to support the liver function, after serious conditions have been excluded by a doctor (monograph of 2018). Its assessment report finds 1.3 to 3 per cent of flavonolignans, silibinin, isosilibinin, silicristin, and silidianin, with 20 to 30 per cent of fatty oil. The trials of its use in liver disease are less favourable. A Cochrane review of 2007, of eighteen trials in 1,088 patients with alcoholic or viral liver disease, found no significant effect on mortality, complications, or liver histology, and its results “question the beneficial effects of milk thistle” in these diseases. A Cochrane review of 2025, in metabolic fatty liver disease, found the benefits and harms unclear: silymarin alone may lower liver enzymes against placebo, on low or very low certainty evidence. LiverTox, revised in 2020, likewise records that controlled trials in chronic hepatitis C and fatty liver disease found little or no evidence of benefit, and that intravenous silibinin is approved in Europe for poisoning by the mushroom *Amanita phalloides*. A 2025 network meta-analysis in type 2 diabetes found that silymarin significantly improved fasting glucose and HbA1c against placebo. ## Pharmacognosy and toxicology - **silymarin**: the mixture of flavonolignans, 1.3 to 3 per cent - **silibinin**: chief of the flavonolignans; given intravenously in Europe for death-cap poisoning - **isosilibinin**: - **silicristin**: - **silidianin**: **Mechanism.** Not established in the sources read for this entry. **Standing.** European Union herbal monograph (2018): traditional use, “exclusively based upon long-standing use,” for digestive disorders and to support liver function. Cochrane reviews (2007, 2025) find no clear benefit in liver disease. ## What lore surrounds it? Folkard gives the legend of the name: the thistle is called the Milk Thistle “from a supposition that it derived the colour of its leaves from the Milk of the Virgin Mary having fallen on them as she suckled the infant Jesus.” ## What did the older authorities say? **Dioscorides, *De materia medica* 4.159.** His *silubon*, which the modern translators suggest is the milk thistle, is a broad *acantha* with leaves like the white chamaeleon. Newly sprung up, it is eaten boiled with oil and salt, and the juice of the root, a teaspoonful drunk with honey and water, “encourages vomiting.” ## Sources - Dioscorides. *De materia medica*, 4-159, in the modern English version of T. A. Osbaldeston and R. P. A. Wood (Johannesburg: Ibidis, 2000), after Goodyer’s translation of 1655. Internet Archive. - Folkard, R. (1884). *Plant Lore, Legends, and Lyrics*, “Milk Thistle.” Project Gutenberg, 44638. - European Medicines Agency, Committee on Herbal Medicinal Products. *European Union herbal monograph on Silybi mariani fructus (Milkthistle Fruit)*. EMA/HMPC/294187/2013, 5 June 2018. - European Medicines Agency, Committee on Herbal Medicinal Products. *Assessment report on Silybi mariani fructus*. EMA/HMPC/294188/2013, 5 June 2018. - Rambaldi A, et al. (2007). Milk thistle for alcoholic and/or hepatitis B or C virus liver diseases. *The Cochrane database of systematic reviews*. PMID 17943794. - Wang C, et al. (2025). Silymarin for adults with metabolic dysfunction-associated steatotic liver disease. *The Cochrane database of systematic reviews*. PMID 40552569. - Miao R, et al. (2025). Clinical Efficacy of Curcumin, Resveratrol, Silymarin, and Berberine on Cardio-Metabolic Risk Factors Among Patients With Type 2 Diabetes Mellitus: A Systemic Review and Bayesian Network Meta-Analysis. *Phytotherapy research : PTR*. PMID 40439602. - LiverTox: Clinical and Research Information on Drug-Induced Liver Injury, “MilkThistle.” National Institute of Diabetes and Digestive and Kidney Diseases, updated 2020. NCBI Bookshelf. - European Medicines Agency, Committee on Herbal Medicinal Products. *European Union herbal monograph on Silybi mariani fructus (Milkthistle Fruit)*. EMA/HMPC/294187/2013, 5 June 2018. - European Medicines Agency, Committee on Herbal Medicinal Products. *Assessment report on Silybi mariani fructus*. EMA/HMPC/294188/2013, 5 June 2018. - Rambaldi A, et al. (2007). Milk thistle for alcoholic and/or hepatitis B or C virus liver diseases. *The Cochrane database of systematic reviews*. PMID 17943794. - Wang C, et al. (2025). Silymarin for adults with metabolic dysfunction-associated steatotic liver disease. *The Cochrane database of systematic reviews*. PMID 40552569. - LiverTox: Clinical and Research Information on Drug-Induced Liver Injury, “MilkThistle.” National Institute of Diabetes and Digestive and Kidney Diseases, updated 2020. NCBI Bookshelf. --- *Milk thistle.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-10-16. The Thinking Press. https://thethinkingpress.org/materia-medica/milk-thistle Historical description, not medical advice.