Milk Thistle History: Pliny's Sillybum to Silymarin Trials

Pliny described a prickly plant he called sillybum and judged it of no use in medicine. The silymarin trials that followed still disagree, and the record shows why: study quality, product variation and the populations tested.

Pliny the Elder described a prickly plant he called *sillybum* and judged it of no use in medicine. Milk thistle's liver research came centuries later and still disagrees about what the extract does. **Jump to:** [Sillybum](#the-sillybum-passage-and-the-modern-name), [Seeds](#why-the-seeds-matter), [Trials](#what-the-trials-tested), [Disagreement](#why-the-results-disagree), [FAQ](#frequently-asked-questions), [Bottom line](#bottom-line) ## The sillybum passage and the modern name Pliny's passage is *Natural History* book 22, chapter 42, in the English text that the [Perseus Digital Library](https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.02.0137%3Abook%3D22%3Achapter%3D42) hosts (Bostock and Riley, 1855). He says the plant is "quite as prickly" as the white chamaeleon, that people where it grew did not think it worth boiling, and that it "is of no use whatever in medicine." The translation's note cites Sprengel, who identified it with *Carduus marianus*, and Fée, who inclined toward the marsh sow-thistle. The modern name is clearer. The [National Center for Complementary and Integrative Health (NCCIH)](https://www.nccih.nih.gov/health/milk-thistle) gives the Latin name as *Silybum marianum*, lists *Carduus marianus* as a synonym, and says the plant was historically used for liver disorders and to increase breast milk production. [Our vitamin B12 history](/blog/history/history-of-vitamin-b12-from-liver-cure-to-cobalamin) opens with a liver-based treatment. Our [turmeric history](/blog/history/history-of-turmeric-and-curcumin-from-ayurveda-to-isolation) covers a similar path. ## Why the seeds matter According to PubMed, a 2010 review describes the active complex as a lipophilic extract from the seeds, made of three flavonolignans: silybin, silydianin and silychristin, together called silymarin. Silybin is the most biologically active of the three. It makes up 50% to 70% of the mixture, and the review says silymarin runs through the whole plant but is concentrated in the fruit and seeds ([review, DOI](https://doi.org/10.1002/ptr.3207)). The sources we checked do not date when the compounds were identified, so this page gives no year. ## What the trials tested According to PubMed, the table covers four randomized, placebo-controlled trials and one pooled review. | Year | Study | Who was studied | Silymarin and length | What it found | |---|---|---|---|---| | 1989 | [Ferenci et al.](https://pubmed.ncbi.nlm.nih.gov/2671116/) | 170 people with cirrhosis | 140 mg three times daily, mean follow-up 41 months | 4-year survival 58% on silymarin, 39% on placebo (P = 0.036) | | 1998 | [Parés et al.](https://pubmed.ncbi.nlm.nih.gov/9566830/) | 200 alcoholics with cirrhosis | 150 mg three times daily, 2 years | No effect on survival or on the course of the disease | | 2007 | [Cochrane review](https://doi.org/10.1002/14651858.CD003620.pub3) (Rambaldi et al.) | 18 trials, 1,088 people with alcoholic or hepatitis B or C liver disease | Varied | No significant effect on mortality overall (RR 0.78, 95% CI 0.53 to 1.15) | | 2012 | [Fried et al., JAMA](https://doi.org/10.1001/jama.2012.8265) | 154 people with chronic hepatitis C who had not responded to interferon | 420 or 700 mg three times daily, 24 weeks | No difference from placebo in ALT or HCV RNA | | 2019 | [Navarro et al., PLoS One](https://doi.org/10.1371/journal.pone.0221683) | 78 randomized people with non-alcoholic steatohepatitis and no cirrhosis | 420 or 700 mg three times daily, 48 weeks | Primary endpoint reached by 12% on placebo, 19% at 420 mg and 15% at 700 mg (P = 0.79) | The 1989 and 1998 cirrhosis trials reached opposite conclusions about survival. The 2012 and 2019 trials tested doses that both sets of authors called higher than customary, and neither showed a benefit on its main measure. ## Why the results disagree Study quality comes first. The [2007 Cochrane review](https://doi.org/10.1002/14651858.CD003620.pub3) found that liver-related mortality was lower when all trials were pooled (RR 0.50, 95% CI 0.29 to 0.88), but not when only the high-quality trials were pooled (RR 0.57, 95% CI 0.28 to 1.19). The second is the product. [Fenclova and colleagues](https://doi.org/10.1038/s41598-019-47250-0) tested 26 milk thistle supplements bought in the United States and Czech markets. They found silymarin content that differed widely between products, often in contrast with what manufacturers stated, and substantial differences between batches. They also reported mycotoxins, pesticide residues and microbial contamination in the preparations they tested, and they suggest product variation may help explain inconsistent clinical results. Our [supplement safety guide](/health/vitamin-d-complete-guide/supplement-safety-quality-testing-guide) covers how to read a label. ## Medicines and interactions In nine healthy volunteers who took a standardized extract three times daily for 14 days, [Kawaguchi-Suzuki and colleagues](https://doi.org/10.1124/dmd.114.057232) found no significant change in four enzymes that process common drugs. Two rat studies show a different picture. A milk thistle component, silybinin, raised the oral bioavailability of loratadine ([Li and colleagues](https://pubmed.ncbi.nlm.nih.gov/20662320/)), and a related compound, silibinin, did the same for paclitaxel ([Lee and Choi](https://doi.org/10.1159/000312690)). In both studies, intravenous doses were not affected. A [2019 review](https://doi.org/10.1002/ptr.6361) described few interactions but advised caution with drugs that have a narrow safety margin. If you want to check a label against this history, our [Milk Thistle 200 mg, 60 vegetarian capsules](https://mtangelvitamins.com/products/milk-thistle-60-ct-vegetarian?utm_source=learn_hub&utm_medium=content&utm_campaign=blog_post&utm_content=history-of-milk-thistle-from-dioscorides-to-silymarin) lists 200 mg of milk thistle fruit extract per capsule, standardized to 80% silybin and silymarin. The product page lists $19.99 for 60 capsules, about $0.33 a capsule, or roughly $0.67 to $1.33 a day at the label's one to two capsules twice daily. The page says the product supports healthy liver function. *These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.* ## Frequently asked questions ### Which classical writers recorded milk thistle? Pliny's *Natural History* describes a prickly plant called *sillybum*. In book 22, chapter 42, he says people where it grew did not think it worth boiling, and he calls it of no use in medicine. Its translation note links the plant to milk thistle through Sprengel, but offers a second identification as well. We did not verify a Dioscorides passage, so this page makes no such claim. ### Why do the seeds matter more than the leaves? According to a 2010 review, the active complex is a lipophilic extract from the seeds, and silymarin is concentrated in the fruit and seeds. The trials in the table tested silymarin preparations. A 2019 product study found measured silymarin often differed from label claims, which is why, in practice, the label alone does not tell you how much silymarin a capsule holds. ### What did the early liver trials test? The 1989 trial randomized 170 people with cirrhosis to 140 mg of silymarin three times daily or placebo, with a mean follow-up of 41 months, and reported 4-year survival of 58% on silymarin against 39% on placebo. The 1998 trial randomized 200 alcoholics with cirrhosis to 150 mg three times daily for two years and found no effect on survival or on the course of the disease. Both measured survival, and they reached opposite conclusions. ### Why do the trial results vary so much? Three things show up in the sources. Study quality: the 2007 Cochrane review found only 28.6% of its trials reported high-quality methods. Product variation: a 2019 study of 26 supplements found silymarin content that differed widely between products and between batches. Design: the trials tested different people at doses from 140 mg three times daily to 700 mg three times daily, and the endpoints differed too. NCCIH describes the overall record as conflicting or too limited. ### How does milk thistle interact with medicines? The human data are small. In nine healthy volunteers, a standardized extract taken for 14 days produced no significant change in four drug-metabolizing enzymes. Rat studies found that milk thistle compounds raised oral bioavailability of two drugs, loratadine and paclitaxel, and one author group advised close monitoring. None of the human studies in the sources we checked tested those two drugs. NCCIH advises talking with a health care provider before using milk thistle with any medicine. ### Is milk thistle regulated like a drug in the United States? No. Milk thistle is sold as a dietary supplement, and NCCIH notes that such products are not approved by the FDA before they are sold. Manufacturers are responsible for evaluating the safety and labeling of their products, and the FDA can act when public health concerns arise. We did not verify a regulatory status for Germany, so this page does not describe one. ## Bottom line Treat the milk thistle record as real but mixed. The trials disagree on survival and on the main outcomes of the later studies. When you read a result, check the population, the dose, the study quality and what the bottle actually contains. The line I keep returning to is Pliny's remark about boiling. People where the plant grew, he says, did not think it worth the trouble, and he judged it useless in medicine. Centuries later, the question is still being tested. **Next reads** - [Safe Supplements: How to Know What You Are Actually Getting](/health/vitamin-d-complete-guide/supplement-safety-quality-testing-guide), on reading a label and what third-party testing shows. - [Turmeric and Curcumin: From Eastern Texts to the Capsule](/blog/history/history-of-turmeric-and-curcumin-from-ayurveda-to-isolation), another herb's history. ### Related reading - [Garlic from pyramid workers to allicin](/blog/history/history-of-garlic-from-pyramid-workers-to-allicin) - [St John's wort and the drug interaction record](/blog/history/history-of-st-johns-wort-from-dioscorides-to-drug-interactions)