Herbal Teas & Extracts · Herbal tea
Milk Thistle Tea
Silybum marianum (L.) Gaertn. · also called Milk thistle fruit tea, Mary thistle tea, holy thistle tea, cardo mariano tea
Milk thistle tea is a drink made from the crushed fruit (often called seeds) of the milk thistle plant. People drink it for the liver and for digestion. We found no trial of the tea itself; the studies tested concentrated extracts and gave mixed or null results for most liver diseases. The main cautions: allergy if you react to ragweed or daisy-family plants, pregnancy and breastfeeding, and some medicines.
General information, not medical advice. Last substantive update · Not medically reviewed. A named clinician has not signed off on this page. How this page is made
About Milk Thistle Tea
Milk thistle tea is the crushed fruit of the plant in hot water. No trial has tested it, and nobody has measured how much silymarin is in a cup, so extract results cannot be assumed for tea. Check the cautions first: allergy for people sensitive to ragweed and the daisy family, no recommendation in pregnancy or breastfeeding, and ask-first with several medicines.
What milk thistle tea is
Milk thistle tea is made from the fruit (often called the seed) of Silybum marianum, in the daisy family, Asteraceae (name checked in GBIF). The EU monograph lists a herbal tea among the forms of the traditional medicine.
The compounds people talk about are called silymarin, and the main one is silibinin. A 2024 review calls silibinin insoluble in water with poor absorption. A 2026 lab study of a boiling-water seed decoction found trace elements and antioxidant activity, but its abstract gives no silymarin amount.
No source we read reports caffeine in this tea. The plant is not a true tea plant, so none would be expected, but that was not tested. Blends can add black or green tea, so read the label.
Tea and extract capsules are not the same
Almost every trial used concentrated extract. We found no trial of the tea. The only tea-related papers are lab chemistry and mould surveys.
This page gives no amounts, because no study shows an amount of tea that works. Ask a doctor or pharmacist what is right for you.
What the research found
For the liver, results are mixed. A large NIH-funded trial found no benefit in hepatitis C. The 2007 Cochrane review of 18 small trials found no clear effect on death. The 2025 Cochrane review of fatty liver rates the evidence low to very low.
Small pooled trials suggest lower blood sugar, rated low quality. Breast milk supply is unclear.
Hospital doctors use purified silibinin by vein for death-cap mushroom poisoning. That is a different product and an emergency treatment; tea is not a cure.
At a glance
Traditional uses history, not proof
- Milk thistle has been used in European folk medicine for the liver, and NCCIH says historically also to increase breast milk production.
- The EU medicines agency accepts the fruit as a traditional medicine for indigestion and to support the liver, based on long use only; its monograph lists a herbal tea form.
Studied for research
- Fatty liver (extract), low
- Hepatitis C (extract), against
- Alcohol-related and viral liver disease (extract), insufficient
- Liver injury from tuberculosis drugs (extract), low
- Blood sugar in type 2 diabetes (extract), low
- Cholesterol and blood fats (extract), mixed
- Breast milk supply, insufficient
- Death-cap poisoning (hospital silibinin, not tea), very-low
- The tea itself, insufficient
Main compounds
- Silymarin, a mix of flavonolignans
- Silibinin (silybin), the main component of silymarin
Common forms
- Crushed dried fruit (seed) for tea
- Tea bags
- Powder
- Standardised extract capsules (used in the trials; not the same as tea)
- Purified silibinin given in hospital (a separate medicine)
Research links: NCCIH: Milk thistle · EMA: Milk thistle fruit herbal medicine · Cochrane: milk thistle for liver diseases (abstract) · Hepatitis C trial of silymarin (abstract) · Silibinin absorption review (abstract) · Contaminants in milk thistle supplements (abstract) · Research Library · Genes & Biomarkers Library
What it is and its history
- Accepted scientific name
- Silybum marianum (L.) Gaertn.
- Naming authority
- (L.) Gaertn.
- Synonyms
- Carduus marianus L.
- Common names
- Milk thistle tea (English); Milk thistle fruit tea (English); Mary thistle tea (English); Holy thistle tea (English); Te de cardo mariano (Spanish); Mariendistel-Tee (German)
- Family or group
- Asteraceae (daisy family)
- Classification
- Plantae > Asteraceae > Silybum > Silybum marianum
- Native range
- NCCIH says native to Europe and introduced into North America by early colonists.
- Habitat
- Not read.
- What it looks like
- Part used: The fruit (often called the seed), crushed or whole for tea. NCCIH describes a tall plant with large purple flowers.
- Cultivation
- Not read.
- Harvest and processing
- Not read.
- Look-alikes and adulterants
- Name: Blessed thistle (Cnicus benedictus); Note: A different plant sold as a bitter tea; not the same.; Name: Other thistles; Note: Common names overlap; check the Latin name Silybum marianum on the label.
- Sustainability and conservation
- Not assessed in the sources read.
Photographs
Traditional use and history history, not clinical proof
| Tradition or era | Documented use | Source |
|---|---|---|
| European folk and traditional medicine | NCCIH says milk thistle was used historically for liver disorders and to increase breast milk production. The EU accepts the fruit as a traditional medicine for indigestion and to support the liver, based on long use only; its monograph lists a herbal tea form. | NCCIH page (read 2026-10-25) and EU monograph |
Traditional use shows how it was used. It does not show that it works or is safe today.
What is inside, and how it may work
What it contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.
Main compounds
| Compound | Family | Where it is concentrated | Activity studied | Level of evidence |
|---|---|---|---|---|
| Silymarin (mix of flavonolignans) PubChem 5213 | flavonolignan complex | Fruit | The extract behind most research. Antioxidant and anti-inflammatory in lab and animal work. Poorly absorbed in people. The amount in tea is not known. 19 36 1 | Laboratory research |
| Silibinin (silybin) PubChem 31553 | flavonolignan | Fruit | The main component of silymarin. A 2024 review calls it insoluble in water with poor absorption, which is why makers build new forms. 19 29 | Laboratory research |
Mechanisms, receptors and pathways
| Target or pathway | Gene or receptor | What was found | Level |
|---|---|---|---|
| Drug-processing enzymes (CYP3A4, CYP2C9, UGT) | CYP3A4, CYP2C9, UGT1A1 | Silybin blocked these enzymes in test-tube work. In human studies of extract the effect was small. A review says many lab effects use concentrations too high to matter in real life. 32 12 36 | Laboratory research |
Absorption, metabolism and elimination
- Absorption
- Poor by mouth: silymarin compounds are quickly joined to sugar or sulphate groups in the gut and liver and some are pumped back into the gut. Only about 1 to 5 percent of a dose leaves in urine.
- Distribution
- Not read.
- Metabolism
- Mostly conjugation; oxidation plays a minor role.
- Elimination
- Not read in detail.
- Bioavailability
- Poor. Silibinin is described as insoluble in water. Not measured for tea.
Isolated compounds versus whole extracts
Nearly all trials used concentrated extracts of silymarin, often at amounts that a cup of tea is not shown to reach. A tea is a water infusion of crushed fruit. A 2026 lab study of a boiling-water decoction of the seeds found trace elements and antioxidant activity and its authors suggest seed tea could supply silymarin, but its abstract gives no silymarin amount, and it was not tested in people. So extract results cannot be assumed for tea.
Nutritional composition
The 2026 lab decoction study found trace elements such as iron, copper, manganese and zinc mostly as free ions. No amount per cup is given in the abstract, and it is not a studied source of nutrients.
1 mixed findings4 low certainty1 very low certainty4 not enough evidence1 evidence against
What was looked at
The 11 benefits and uses checked for Milk Thistle Tea, each with how strong the evidence is. Tap one to open it.
- Milk thistle tea itself, for the liver or for digestionNot enough evidence
- Fatty liver disease (trials used extract capsules, not tea)Low certainty
- Hepatitis C (extract trial)Evidence against
- Alcohol-related and viral liver disease (hepatitis B or C), pooledNot enough evidence
- Liver injury from tuberculosis drugs (extract trials)Low certainty
- Death-cap mushroom poisoning (hospital medicine, not tea)Very low certainty
- Indigestion and fullness (traditional use)Not enough evidence
- Blood sugar in type 2 diabetes (extract trials)Low certainty
- Cholesterol and blood fats (extract trials)Mixed findings
- Breast milk supply (silymarin among many tested)Not enough evidence
- Skin reactions to breast radiotherapy (silymarin applied to skin)Low certainty
Lab markers tracked in the studies
Liver enzymes ALT and ASTFasting blood sugar and HbA1cTotal cholesterol and triglyceridesInsulin resistance (HOMA-IR)
What is Milk Thistle Tea good for?
The uses people ask about and how strong the evidence is for each. Read the certainty label first: every result here comes from extracts or purified compounds, not from a cup of tea.
Benefits, one by one
Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.
Milk thistle tea itself, for the liver or for digestion
Not enough evidenceNo trial has tested the tea in people. The EU accepts the fruit as a traditional medicine for the liver and for indigestion, on long use alone.
3 studiesNot shown on this page.
Studies, doses and limits
What the trials found
No human trial of milk thistle tea was found. The EU monograph lists a tea form for traditional use only, after a doctor has ruled out serious conditions. NCCIH says there is not enough high-quality evidence for firm conclusions on any health use.
Results
Not shown for the tea.
Why this rating
Nothing was tested in people with the tea. Traditional use is not proof it works.
Form and dose studied
Not shown on this page.
Who was studied
Adults in traditional use; no trial population.
Limits
The tea has not been tested, and a cup may carry very little silymarin (see the science tab).
Why researchers looked
Milk thistle is best known as a liver herb, and tea is the simplest way to take it.
Traditional use
Milk thistle fruit has a long history in European folk medicine for the liver. The EU medicines agency accepts it as a traditional medicine on long use only; its monograph lists a herbal tea form.
Proposed mechanism Traditional use
Silymarin, a mix of compounds from the fruit, acts as an antioxidant and calms inflammation in lab and animal work. It is poorly absorbed, and a tea is not a concentrated extract, so how much of this applies to a cup is unknown.
A proposed mechanism does not show that the effect happens in people.
See the safety tab: daisy-family allergy, pregnancy, and medicines. Anyone with liver disease needs a doctor, not a tea.
Fatty liver disease (trials used extract capsules, not tea)
Low certaintyPooled trials of extract found lower liver enzymes and some less liver fat, but the best Cochrane review rates the evidence low to very low, and one NIH-funded trial found no benefit.
3 studiesNot shown on this page.
Studies, doses and limits
What the trials found
Meta-analysis of 26 trials (2,375 people) found lower ALT and AST and less liver fat. The 2025 Cochrane review (17 trials, 2,069 people) found silymarin alone may lower ALT, but the evidence is low to very low in certainty and no trial reported death or quality of life. An NIH-funded trial in 78 people with fatty liver and inflammation found no benefit in the main analysis.
Results
Lower liver enzymes in pooled trials; no benefit in the best-designed single trial.
Effect sizes as reported
Cochrane 2025: ALT -7.21 U/L (CI -10.62 to -3.80), very low certainty. Meta-analysis 2024: steatosis OR 3.25 (1.80 to 5.87). NASH trial: 15 and 19 percent vs 12 percent on placebo (P = 0.79).
Why this rating
Pooled results point one way but come from small, varied trials; the Cochrane authors rate the certainty low to very low; one rigorous trial was null; none used tea.
Form and dose studied
Not shown on this page.
Who was studied
Adults with fatty liver (NAFLD/MASLD, NASH).
Limits
Extract, not tea. Many trials were short. Liver blood tests are markers, not outcomes.
Why researchers looked
Fatty liver is very common and has few approved treatments.
Traditional use
Milk thistle fruit has a long history in European folk medicine for the liver. The EU medicines agency accepts it as a traditional medicine on long use only; its monograph lists a herbal tea form.
Proposed mechanism Laboratory research
Silymarin, a mix of compounds from the fruit, acts as an antioxidant and calms inflammation in lab and animal work. It is poorly absorbed, and a tea is not a concentrated extract, so how much of this applies to a cup is unknown.
A proposed mechanism does not show that the effect happens in people.
See the safety tab: daisy-family allergy, pregnancy, and medicines. Anyone with liver disease needs a doctor, not a tea.
Hepatitis C (extract trial)
Evidence againstA large NIH-funded trial found that silymarin extract did not lower liver enzymes or virus levels compared with placebo.
3 studiesNot shown on this page.
Studies, doses and limits
What the trials found
In 154 people with hepatitis C that interferon had not cleared, only 2 people per group reached the main liver-enzyme goal. Virus levels and quality of life did not differ. Side effects matched placebo. NCCIH says the trial showed no benefit.
Results
No benefit over placebo.
Effect sizes as reported
Main goal met by 3.8 to 4.0 percent in every group; ALT fall P = 0.75.
Why this rating
A moderate-sized, placebo-controlled, registered trial found no effect, and the Cochrane review found nothing clear.
Form and dose studied
Not shown on this page.
Who was studied
Adults with chronic hepatitis C that interferon had not cleared.
Limits
One extract, 24 weeks. Not tea.
Why researchers looked
Many people with hepatitis C look for herbs while waiting for or after treatment.
Traditional use
Milk thistle fruit has a long history in European folk medicine for the liver. The EU medicines agency accepts it as a traditional medicine on long use only; its monograph lists a herbal tea form.
Proposed mechanism Laboratory research
Silymarin, a mix of compounds from the fruit, acts as an antioxidant and calms inflammation in lab and animal work. It is poorly absorbed, and a tea is not a concentrated extract, so how much of this applies to a cup is unknown.
A proposed mechanism does not show that the effect happens in people.
Hepatitis C has curing medicines; see a liver specialist.
Alcohol-related and viral liver disease (hepatitis B or C), pooled
Not enough evidenceA Cochrane review of 18 small, mostly low-quality trials found no clear effect on death or complications.
2 studiesNot shown on this page.
Studies, doses and limits
What the trials found
The 2007 Cochrane review (18 trials, 1,088 people) found no significant effect on death (RR 0.78) or complications (RR 0.95). Liver-related death looked lower across all trials (RR 0.50) but not in the higher-quality ones (RR 0.57, CI 0.28 to 1.19). The authors question benefit and call for good trials. A 2017 meta-analysis found liver enzymes fell by amounts without clinical relevance.
Results
No clear effect on death or complications.
Effect sizes as reported
Mortality RR 0.78 (0.53 to 1.15). ALT -0.26 and AST -0.53 IU/mL, no clinical relevance.
Why this rating
Trials were few, small and mostly low quality; results differ.
Form and dose studied
Not shown on this page.
Who was studied
Adults with alcohol-related liver disease, hepatitis B or C.
Limits
Old review (2007); extracts, not tea.
Why researchers looked
Milk thistle is widely taken by people with long-term liver disease.
Traditional use
Milk thistle fruit has a long history in European folk medicine for the liver. The EU medicines agency accepts it as a traditional medicine on long use only; its monograph lists a herbal tea form.
Proposed mechanism Laboratory research
Silymarin, a mix of compounds from the fruit, acts as an antioxidant and calms inflammation in lab and animal work. It is poorly absorbed, and a tea is not a concentrated extract, so how much of this applies to a cup is unknown.
A proposed mechanism does not show that the effect happens in people.
Never use a tea in place of treatment for liver disease.
Liver injury from tuberculosis drugs (extract trials)
Low certaintyPooled trials found less liver injury at four weeks with silymarin. The trials were few and small.
3 studiesNot shown on this page.
Studies, doses and limits
What the trials found
A meta-analysis of 5 trials (1,198 people) found less liver injury at week 4 (RR 0.33). A small 55-person trial found 1 of 27 people on silymarin and 9 of 28 on placebo developed liver injury. In children with leukaemia, a 50-child pilot found a trend to lower liver tests at day 56.
Results
Less liver injury in pooled trials.
Effect sizes as reported
RR 0.33 (0.15 to 0.75) at week 4.
Why this rating
Five small trials, short follow-up, extracts, and not tea; the children's trial was a small pilot.
Form and dose studied
Not shown on this page.
Who was studied
Adults starting tuberculosis drugs; children with leukaemia (pilot).
Limits
Extract, not tea.
Why researchers looked
Tuberculosis drugs can injure the liver, and people look for ways to protect it.
Traditional use
Milk thistle fruit has a long history in European folk medicine for the liver. The EU medicines agency accepts it as a traditional medicine on long use only; its monograph lists a herbal tea form.
Proposed mechanism Laboratory research
Silymarin, a mix of compounds from the fruit, acts as an antioxidant and calms inflammation in lab and animal work. It is poorly absorbed, and a tea is not a concentrated extract, so how much of this applies to a cup is unknown.
A proposed mechanism does not show that the effect happens in people.
People on these drugs must follow their doctor's plan.
Death-cap mushroom poisoning (hospital medicine, not tea)
Very low certaintyA purified form of silibinin given into a vein in hospital is used for death-cap poisoning. It is an emergency medicine. A tea cannot treat it.
2 studiesNot shown on this page.
Studies, doses and limits
What the trials found
A review of 877 reported cases found 84 percent survived overall, 59 percent with supportive care alone, and 90 percent with intravenous silibinin. In confirmed poisonings, though, the authors found no statistical difference between treatments. Another review notes there are no controlled trials, only uncontrolled reports.
Results
Better survival in uncontrolled reports; no controlled trials.
Effect sizes as reported
Survival 90 percent with silibinin vs 59 percent with supportive care only (OR 6.40, 3.14 to 13.04), case reports.
Why this rating
Only case reports and series; sicker patients may be treated differently; a different product (purified intravenous silibinin) given by doctors.
Form and dose studied
Not shown on this page.
Who was studied
People poisoned by Amanita mushrooms, treated in hospital.
Limits
This is a hospital treatment of a different form. Milk thistle tea is not an antidote.
Why researchers looked
Silibinin from milk thistle seems to block the death-cap toxin from entering liver cells.
Traditional use
Milk thistle fruit has a long history in European folk medicine for the liver. The EU medicines agency accepts it as a traditional medicine on long use only; its monograph lists a herbal tea form.
Proposed mechanism Laboratory research
Silibinin is described as blocking amatoxin from re-entering liver cells, in lab and animal work.
A proposed mechanism does not show that the effect happens in people.
If you may have eaten a poisonous wild mushroom, call poison control or emergency services at once. In the US call 1-800-222-1222.
Indigestion and fullness (traditional use)
Not enough evidenceThe EU lists the fruit as a traditional medicine for indigestion and a feeling of fullness. This rests on long use, not trials.
2 studiesNot shown on this page.
Studies, doses and limits
What the trials found
The EU monograph accepts traditional use for symptomatic relief of digestive disorders and fullness, for adults, after serious conditions are ruled out, and says to see a doctor if symptoms last more than two weeks.
Results
Not tested.
Why this rating
No trial; regulatory category based on tradition.
Form and dose studied
Not shown on this page.
Who was studied
Adults, traditional use.
Limits
No trial of the tea or fruit for digestion was found.
Why researchers looked
Milk thistle fruit is also used as a bitter digestive herb in folk medicine.
Traditional use
Milk thistle fruit has a long history in European folk medicine for the liver. The EU medicines agency accepts it as a traditional medicine on long use only; its monograph lists a herbal tea form.
Proposed mechanism Traditional use
Silymarin, a mix of compounds from the fruit, acts as an antioxidant and calms inflammation in lab and animal work. It is poorly absorbed, and a tea is not a concentrated extract, so how much of this applies to a cup is unknown.
A proposed mechanism does not show that the effect happens in people.
See a doctor if indigestion lasts or if there is weight loss, vomiting or black stools.
Blood sugar in type 2 diabetes (extract trials)
Low certaintyPooled small trials found lower fasting blood sugar and HbA1c with silymarin extract. The authors rate quality low, and NIH says most trials were from the Middle East.
3 studiesNot shown on this page.
Studies, doses and limits
What the trials found
A meta-analysis of 5 trials (270 people) found fasting blood sugar lower by about 27 mg/dL and HbA1c by about 1 point. A 2025 meta-analysis of 6 trials (673 people) found a borderline fall in insulin resistance (HOMA-IR) but no change in fasting insulin. The authors of the 2016 review say no recommendation can be made.
Results
Lower blood sugar markers in small trials.
Effect sizes as reported
Fasting glucose -26.86 mg/dL (CI -35.42 to -18.30); HbA1c -1.07 (CI -1.73 to -0.40). HOMA-IR WMD -2.29 (CI -4.55 to -0.03).
Why this rating
Few, small, varied trials of low quality, mostly from a few countries; none used tea.
Form and dose studied
Not shown on this page.
Who was studied
Adults with type 2 diabetes.
Limits
Extract, not tea. Trials small.
Why researchers looked
Silymarin is studied as an add-on in type 2 diabetes.
Traditional use
Milk thistle fruit has a long history in European folk medicine for the liver. The EU medicines agency accepts it as a traditional medicine on long use only; its monograph lists a herbal tea form.
Proposed mechanism Laboratory research
Silymarin, a mix of compounds from the fruit, acts as an antioxidant and calms inflammation in lab and animal work. It is poorly absorbed, and a tea is not a concentrated extract, so how much of this applies to a cup is unknown.
A proposed mechanism does not show that the effect happens in people.
If you use diabetes medicine, extra blood-sugar lowering is possible in theory; talk to your care team.
Cholesterol and blood fats (extract trials)
Mixed findingsOne pooled analysis found lower cholesterol and triglycerides; another found no effect on blood fats in diabetes. Results conflict.
2 studiesNot shown on this page.
Studies, doses and limits
What the trials found
A meta-analysis of 11 trials found lower total cholesterol, triglycerides and LDL and higher HDL, but with high heterogeneity. The 2016 diabetes meta-analysis found no lipid effect.
Results
Mixed.
Effect sizes as reported
Total cholesterol -17.46 mg/dL (CI -30.98 to -3.95); diabetes review: no effect on lipids.
Why this rating
Two pooled analyses disagree; trials differ a lot.
Form and dose studied
Not shown on this page.
Who was studied
Adults with metabolic syndrome or diabetes.
Limits
High heterogeneity; extracts.
Why researchers looked
Fatty liver and diabetes often come with raised blood fats.
Traditional use
Milk thistle fruit has a long history in European folk medicine for the liver. The EU medicines agency accepts it as a traditional medicine on long use only; its monograph lists a herbal tea form.
Proposed mechanism Laboratory research
Silymarin, a mix of compounds from the fruit, acts as an antioxidant and calms inflammation in lab and animal work. It is poorly absorbed, and a tea is not a concentrated extract, so how much of this applies to a cup is unknown.
A proposed mechanism does not show that the effect happens in people.
Do not stop prescribed cholesterol medicine.
Breast milk supply (silymarin among many tested)
Not enough evidenceThe Cochrane review could not say whether silymarin or any natural milk booster works. LactMed says no valid trials support the claim.
2 studiesNot shown on this page.
Studies, doses and limits
What the trials found
A 2020 Cochrane review of 41 trials (3,005 mothers) found evidence for natural boosters, silymarin among them, was low to very low in certainty and too varied to pool. LactMed (summary) says no scientifically valid clinical trials support milk-supply claims.
Results
Unclear.
Effect sizes as reported
Not pooled.
Why this rating
Low to very low certainty; silymarin is only one of many agents.
Form and dose studied
Not shown on this page.
Who was studied
Breastfeeding mothers of term babies.
Limits
Not specific to silymarin or tea.
Why researchers looked
Milk thistle has been used by nursing mothers for centuries.
Traditional use
Milk thistle fruit has a long history in European folk medicine for the liver. The EU medicines agency accepts it as a traditional medicine on long use only; its monograph lists a herbal tea form.
Proposed mechanism Laboratory research
Silymarin, a mix of compounds from the fruit, acts as an antioxidant and calms inflammation in lab and animal work. It is poorly absorbed, and a tea is not a concentrated extract, so how much of this applies to a cup is unknown.
A proposed mechanism does not show that the effect happens in people.
The EU does not recommend milk thistle during breastfeeding for lack of data; talk to a lactation professional.
Skin reactions to breast radiotherapy (silymarin applied to skin)
Low certaintyA review says silymarin applied to the skin showed positive effects, but the abstract gives no numbers. It is not a drink.
1 studiesNot shown on this page.
Studies, doses and limits
What the trials found
A 2024 review of 16 studies (1,994 patients) says silymarin showed positive effects on radiation skin damage, with more trials needed.
Results
Positive in the review's wording.
Effect sizes as reported
No numbers given in the abstract.
Why this rating
Topical use only; abstract gives no figures.
Form and dose studied
Not shown on this page.
Who was studied
Women having breast radiotherapy.
Why researchers looked
Radiotherapy burns the skin and few creams are proven.
Traditional use
Milk thistle fruit has a long history in European folk medicine for the liver. The EU medicines agency accepts it as a traditional medicine on long use only; its monograph lists a herbal tea form.
Proposed mechanism Laboratory research
Silymarin, a mix of compounds from the fruit, acts as an antioxidant and calms inflammation in lab and animal work. It is poorly absorbed, and a tea is not a concentrated extract, so how much of this applies to a cup is unknown.
A proposed mechanism does not show that the effect happens in people.
Ask your cancer team before putting anything on irradiated skin.
Connections to the rest of health
How Milk Thistle Tea connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.
Explore every connection: goals, body systems, organs, symptoms, genes
A. Wellness goals
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Liver Support | Not enough evidence | Milk thistle tea itself, for the liver or for digestion: No trial has tested the tea in people. The EU accepts the fruit as a traditional medicine for the liver and for indigestion, on long use alone. Fatty liver disease (trials used extract capsules, not tea): Pooled trials of extract found lower liver enzymes and some less liver fat, but the best Cochrane review rates the evidence low to very low, and one NIH-funded trial found no benefit. | 5 20 2 15 38 21 9 28 40 34 17 14 33 18 | |
| Digestive Health | Not enough evidence | Milk thistle tea itself, for the liver or for digestion: No trial has tested the tea in people. The EU accepts the fruit as a traditional medicine for the liver and for indigestion, on long use alone. Indigestion and fullness (traditional use): The EU lists the fruit as a traditional medicine for indigestion and a feeling of fullness. This rests on long use, not trials. | 5 20 2 | |
| Blood Sugar Balance | Low certainty | Blood sugar in type 2 diabetes (extract trials): Pooled small trials found lower fasting blood sugar and HbA1c with silymarin extract. The authors rate quality low, and NIH says most trials were from the Middle East. | 37 39 20 | |
| Heart Health | Mixed findings | Cholesterol and blood fats (extract trials): One pooled analysis found lower cholesterol and triglycerides; another found no effect on blood fats in diabetes. Results conflict. | 31 37 | |
| Womens Wellness | Not enough evidence | Breast milk supply (silymarin among many tested): The Cochrane review could not say whether silymarin or any natural milk booster works. LactMed says no valid trials support the claim. | 8 4 | |
| Skin Health | Low certainty | Skin reactions to breast radiotherapy (silymarin applied to skin): A review says silymarin applied to the skin showed positive effects, but the abstract gives no numbers. It is not a drink. | 26 |
B. Body systems
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Liver | Low certainty | Extract trials in liver disease are mixed or negative. Mixed or null in liver disease trials. Preparation or compound: Extract trials; tea not studied |
28 38 9 | |
| Hepatic System | Biological association | Not enough evidence | Studied for: Milk thistle tea itself, for the liver or for digestion Studied for: Fatty liver disease (trials used extract capsules, not tea) | 5 20 2 15 38 21 9 28 40 34 17 14 33 18 |
| Digestive System | Biological association | Not enough evidence | Studied for: Milk thistle tea itself, for the liver or for digestion Studied for: Indigestion and fullness (traditional use) | 5 20 2 |
| Immune System | Biological association | Evidence against | Studied for: Hepatitis C (extract trial) | 9 28 20 |
| Endocrine System | Biological association | Low certainty | Studied for: Blood sugar in type 2 diabetes (extract trials) | 37 39 20 |
| Cardiovascular System | Biological association | Mixed findings | Studied for: Cholesterol and blood fats (extract trials) | 31 37 |
| Reproductive System | Biological association | Not enough evidence | Studied for: Breast milk supply (silymarin among many tested) | 8 4 |
| Integumentary System | Biological association | Low certainty | Studied for: Skin reactions to breast radiotherapy (silymarin applied to skin) | 26 |
D. Symptoms
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Type 2 diabetes | Low certainty | Lower blood sugar markers in small trials. Preparation or compound: Extract (not tea) |
37 39 |
I. Biomarkers
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Liver enzymes ALT and AST | Biological association | Very low certainty | Measured in trials: lowered. A lab change is not the same as a health benefit. | 38 40 9 |
| Fasting blood sugar and HbA1c | Biological association | Low certainty | Measured in trials: lowered. A lab change is not the same as a health benefit. | 37 |
| Total cholesterol and triglycerides | Biological association | Mixed findings | Measured in trials: mixed. A lab change is not the same as a health benefit. | 31 37 |
| Insulin resistance (HOMA-IR) | Biological association | Low certainty | Measured in trials: lowered. A lab change is not the same as a health benefit. | 39 |
J. Genes, receptors and enzymes
L. Active compounds
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Silymarin (mix of flavonolignans) | Biological association | In vitro | The extract behind most research. Antioxidant and anti-inflammatory in lab and animal work. Poorly absorbed in people. The amount in tea is not known. Preparation or compound: Fruit |
19 36 1 |
| Silibinin (silybin) | Biological association | In vitro | The main component of silymarin. A 2024 review calls it insoluble in water with poor absorption, which is why makers build new forms. Preparation or compound: Fruit |
19 29 |
Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 25, 2026).
The evidence
The research centre for Milk Thistle Tea. Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.
Evidence by outcome
Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).
How we rate evidence
High certainty
Several well-run trials or reviews agree; further research is unlikely to change the picture much.
Moderate certainty
Good trials point the same way, but some doubt remains.
Low certainty
Small, short or inconsistent trials. The finding could change with better research.
Very low certainty
Very little or very weak human data. Treat as a possibility only.
Mixed findings
Trials or reviews disagree with each other.
Not enough evidence
Not enough human research to say either way.
Evidence against
Good research found no benefit, or found harm.
We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We read the abstracts of 32 PubMed papers (one more was title-only), re-opened the NCCIH page and the EU monograph, and used earlier readings of LiverTox, LactMed and GBIF. The LiverTox and LactMed records were read as summaries only.
Study library: every study we checked 41
| Study | Design | People | Product, dose, length | Result |
|---|---|---|---|---|
| Abenavoli 2018 Milk thistle (Silybum marianum): A concise overview on its chemistry, pharmacological, and nutraceutical uses in liver diseases. Phytother Res · PMID 30080294 · DOI |
Review review |
Review of chemistry and liver uses of milk thistle | Milk thistle and silymarin fruit extract Not shown on this page |
Says milk thistle fruits hold a mix of compounds called silymarin, with silybin the main one, and notes a long history of use. It concludes that despite promising lab data, better randomised trials are needed. n/a Methods, limits and fundingOutcomes: Overview Limitations: Narrative review. Read: abstract |
| AlternativeMed editorial search 2026 Search for human trials of milk thistle tea (PubMed and Europe PMC phrase searches, repeated for this page) Search record |
Search record n/a |
n/a | n/a |
No human trial of milk thistle tea was found in the earlier searches recorded for the tea record. The searches were not repeated line by line for this build. Methods, limits and fundingOutcomes: n/a Limitations: A negative search cannot prove nothing exists. Read: summary-only |
| Barbosa 2020 Silymarin administration during pregnancy and breastfeeding: evaluation of initial development and adult behavior of mice. Neurotoxicology · PMID 32084436 · DOI |
Animal research mouse |
Pregnant mice and their young | Silymarin extract Not shown on this page |
No differences in early development. Adult young of treated mothers behaved somewhat differently in some behaviour tests. The authors read this as showing safety. We note it is mouse work and does not show safety in pregnancy. n/a Methods, limits and fundingOutcomes: Development and adult behaviour of the young Limitations: Mice only. Read: abstract |
| Drugs and Lactation Database (NICHD/NIH) 2026 Milk Thistle (LactMed) LactMed, updated 15 March 2026 · PMID 30000830 |
Authoritative guidance |
Breastfeeding mothers and infants | Milk thistle and silymarin fruit (seed) |
Opening summary read (the full record could not be opened). Limited data indicate silymarin components are not excreted into breast milk in measurable amounts; because they are poorly absorbed, an effect on a breastfed infant is judged unlikely. Well tolerated in adults with mild side effects such as diarrhoea, headache and skin reactions; mothers taking it for milk supply occasionally reported weight gain, nausea, dry mouth and irritability. Might increase the metabolism of some drugs. Rarely, severe allergies and anaphylaxis are reported. Avoid with known allergy to the aster (Asteraceae) family, such as daisies, artichokes, common thistle and kiwi, because cross-allergy is possible. States no scientifically valid clinical trials support a milk-supply effect. Methods, limits and fundingOutcomes: Lactation safety summary Limitations: Summary text only; the full LactMed record was not opened. Read: summary-only |
| European Medicines Agency 2018 European Union herbal monograph on Silybum marianum (L.) Gaertn., fructus (EMA/HMPC/294187/2013) EMA monograph, adopted 5 June 2018 · Source |
Authoritative guidance |
Adults and elderly | Milk thistle fruit: herbal tea, powder and extracts fruit (seed) Not shown on this page |
Traditional use only (no well-established use): symptomatic relief of digestive disorders, a feeling of fullness and indigestion, and to support liver function, after serious conditions have been excluded by a doctor. Adults and elderly. A herbal tea is among the listed forms. Contraindication: hypersensitivity to the plant or to Asteraceae (Compositae) plants. Not recommended under 18 (lack of data). Safety in pregnancy and lactation not established; use not recommended. Interactions: none reported. Possible mild stomach and gut effects, headache and allergic reactions. See a doctor if symptoms last over 2 weeks or if yellow skin or eyes or a change in urine or stool colour appear. Adequate tests on reproductive toxicity, genotoxicity and carcinogenicity have not been performed on these preparations. Methods, limits and fundingOutcomes: Regulatory safety statements Limitations: Re-opened 2026-10-25: tea form, Asteraceae contraindication, no reported interactions and pregnancy and lactation statements were confirmed in the PDF text; other lines come from the earlier full reading. Read: partial-text |
| European Medicines Agency 2018 Assessment report on Silybum marianum (L.) Gaertn., fructus (EMA/HMPC/294188/2013) EMA assessment report, 78 pages, 5 June 2018 · Source |
Authoritative guidance |
Adults | Milk thistle fruit preparations fruit (seed) |
Safety, toxicology, interaction and special-population sections read in full; other sections searched. Reports that clinical trials covering more than 4,000 patients (1 to 41 months) were reviewed for safety, with low frequency of adverse events: mild stomach and gut symptoms, headache and allergic reactions; many trials reported no difference from placebo. Trial table lists abdominal pain, diarrhoea, nausea, vomiting, constipation, fatigue and insomnia (similar in both groups, 4 weeks), diarrhoea, gas and fullness (2 percent, 3 months), itching, headache, hives, joint pain (2 years), mild laxative effect (1 month). Company safety reports for the standardised extract: more than 23 million patient-months of exposure (2004 to 2014); the pharmacovigilance database lists no adverse events, serious events or deaths related to milk thistle, as stated in the report. US National Toxicology Program feeding studies of an extract (about 65 percent silymarin): no evidence of cancer-causing activity in rats and mice over 2 years; in 3-month rat studies sperm motility fell by 5 to 11 percent in males at higher doses. Genotoxicity findings were sporadic and inconsistent; the committee judged insufficient genotoxicity data to recommend a list entry. No developmental toxicity data. Drug interactions judged low risk based on indinavir and ranitidine studies. Pregnancy and lactation: not recommended for lack of data. Methods, limits and fundingOutcomes: Non-clinical and clinical safety review Limitations: Read in full for the herb record on 2026-10-24; not re-opened in this build. Read: summary-only |
| Fenclova 2019 Poor chemical and microbiological quality of the commercial milk thistle-based dietary supplements may account for their reported unsatisfactory and non-reproducible clinical outcomes. Sci Rep · PMID 31366891 · DOI |
Other n/a |
26 milk thistle supplements bought in the US and Czech Republic in 2016 to 2017 | Commercial milk thistle supplements fruit extract products Not shown on this page |
Silymarin content differed greatly between products and between batches, often unlike the label. All products had large numbers of mycotoxins, several pesticides and microbial contamination. The authors suggest poor quality may explain mixed trial results and possibly supplement-linked liver injury, which is their suggestion, not proof. n/a Methods, limits and fundingOutcomes: Silymarin content, mycotoxins, pesticides, microbes Limitations: Supplements (extracts), not tea; no tea bags are named. Read: abstract |
| Foong 2020 Oral galactagogues (natural therapies or drugs) for increasing breast milk production in mothers of non-hospitalised term infants. Cochrane Database Syst Rev · PMID 32421208 · DOI |
Systematic review |
3005 Breastfeeding mothers of healthy term babies (41 trials of many natural and drug milk boosters) |
Natural milk boosters including silymarin, compared with placebo or nothing (silymarin was one of many) various, including silymarin Not shown on this page varied · vs placebo, none or another booster |
Evidence was low to very low. Results for natural boosters could not be pooled because the trials differed so much; subgroups pointed to either benefit or little difference. The review cannot say whether any one booster, including silymarin, works. Not pooled Methods, limits and fundingOutcomes: Milk volume, baby weight, continued breastfeeding Limitations: Silymarin was one of many agents; this review does not isolate it. Funding and conflicts: Cochrane review. Read: abstract |
| Fried 2012 Effect of silymarin (milk thistle) on liver disease in patients with chronic hepatitis C unsuccessfully treated with interferon therapy: a randomized controlled trial. JAMA · PMID 22797645 · DOI |
Controlled trial |
154 Adults with chronic hepatitis C that interferon treatment had not cleared |
Milk thistle fruit extract (silymarin), capsules or tablets (not tea) (two higher-than-usual strengths) fruit extract Not shown on this page 24 weeks · vs placebo |
Almost nobody in any group reached the main liver-enzyme target (2 people per group). ALT fell by similar amounts in all groups (P = 0.75). Virus levels and quality of life did not differ. Side effects were similar to placebo. Main outcome met by 4.0 and 3.8 percent vs 3.8 percent on placebo; P at least 0.99 Methods, limits and fundingOutcomes: Liver enzyme ALT, hepatitis C virus level, quality of life, side effects Limitations: Moderate-sized trial of one product in people with hepatitis C that had not responded to treatment. Funding and conflicts: Public funding (NIH) listed; registered NCT00680342. Read: abstract |
| GBIF Secretariat 2026 GBIF Backbone Taxonomy: Silybum marianum (L.) Gaertn., species key 3145214 (with synonyms, vernacular names and name matches for look-alike species) GBIF (database, accessed 2026-10-24) · Source |
Database record n/a |
n/a | n/a |
Accepted species in Asteraceae; 21 synonym records; Silybum has two other accepted species (S. eburneum, S. cernuum); Centaurea benedicta accepted with Cnicus benedictus as synonym. Methods, limits and fundingOutcomes: Accepted name, family, synonyms, vernacular names Limitations: Database may change; distribution not retrieved. Read: summary-only |
| Gufford 2015 Milk Thistle Constituents Inhibit Raloxifene Intestinal Glucuronidation: A Potential Clinically Relevant Natural Product-Drug Interaction. Drug Metab Dispos · PMID 26070840 · DOI |
Lab in vitro |
Human gut tissue and engineered cells | Silybin A and B compound Not shown on this page |
Silybin A and B strongly slowed the gut breakdown of the drug raloxifene. A computer model predicted a 4- to 5-fold rise in raloxifene exposure. The authors say this merits further evaluation. Predicted 4-5 fold Methods, limits and fundingOutcomes: Breakdown of raloxifene in the lab Limitations: Lab and model only. Read: abstract |
| Kawaguchi-Suzuki 2014 The effects of milk thistle (Silybum marianum) on human cytochrome P450 activity. Drug Metab Dispos · PMID 25028567 · DOI |
Clinical trial |
9 9 healthy volunteers |
Milk thistle fruit extract (silymarin), capsules or tablets (not tea) (standardised) fruit extract Not shown on this page 14 days · vs own measurements before treatment |
No significant effect on any of the four enzymes. No significant change Methods, limits and fundingOutcomes: Activity of four drug-processing enzymes (CYP1A2, 2C9, 2D6, 3A4/5) Limitations: Only nine people; one extract; not tea. Funding and conflicts: Public funding (NIH) listed. Read: abstract |
| Kim 2010 Effects of silybinin on the pharmacokinetics of tamoxifen and its active metabolite, 4-hydroxytamoxifen in rats. Anticancer Res · PMID 20150620 |
Animal research rat |
Rats | Silybinin with tamoxifen compound Not shown on this page |
Silybinin raised tamoxifen exposure by about 40 to 71 percent in rats. No human data. 40.2 to 71.3 percent higher exposure Methods, limits and fundingOutcomes: Tamoxifen blood levels Limitations: Rats only. Read: abstract |
| Ladas 2010 A randomized, controlled, double-blind, pilot study of milk thistle for the treatment of hepatotoxicity in childhood acute lymphoblastic leukemia (ALL). Cancer · PMID 20014183 · DOI |
Controlled trial |
50 Children with leukaemia and liver damage from chemotherapy |
Milk thistle fruit extract (silymarin), capsules or tablets (not tea) (children) fruit extract Not shown on this page 28 days · vs placebo |
No clear change in liver tests at day 28. At day 56 AST was lower with milk thistle (P = 0.05) and ALT showed a trend (P = 0.07). Side effects did not differ. Milk thistle did not block chemotherapy action in lab cells. AST lower at day 56, P = 0.05 Methods, limits and fundingOutcomes: Liver tests, side effects, infections Limitations: Small pilot; the authors call for more study. Funding and conflicts: Public funding (NIH) listed. Read: abstract |
| Li 2024 Administration of silymarin in NAFLD/NASH: A systematic review and meta-analysis. Ann Hepatol · PMID 38579127 · DOI |
Systematic review |
2375 People with fatty liver disease (NAFLD/NASH), 26 randomised trials |
Milk thistle fruit extract (silymarin), capsules or tablets (not tea) (various) fruit extract Not shown on this page varied · vs placebo or other |
Silymarin lowered total and LDL cholesterol, triglycerides, ALT and AST, and liver fat on scans or biopsy (steatosis OR 3.25). The authors say the effects need to be confirmed. The 2025 Cochrane review rated the same kind of evidence low to very low. Steatosis improved: OR 3.25 (1.80 to 5.87) Methods, limits and fundingOutcomes: Cholesterol, insulin, liver enzymes, liver fat Limitations: Pooled results; the abstract gives no quality grading; trials differ. Extracts, not tea. Read: abstract |
| LiverTox 2020 Milk Thistle (LiverTox) LiverTox: Clinical and Research Information on Drug-Induced Liver Injury, 21 January 2020 · PMID 31644124 |
Authoritative guidance |
General | Milk thistle fruit (seed) |
Opening statement read: 'Milk thistle has not been implicated in causing liver injury and is still used widely as a liver tonic in patients with acute and chronic liver diseases.' The full entry (likelihood score, case list, monitoring advice) could not be opened because the NIH page blocks automated access. Methods, limits and fundingOutcomes: Liver safety statement Limitations: Opening statement only; the full LiverTox entry (likelihood score) was not opened. Read: summary-only |
| Luangchosiri 2015 A double-blinded randomized controlled trial of silymarin for the prevention of antituberculosis drug-induced liver injury. BMC Complement Altern Med · PMID 26400476 · DOI |
Controlled trial |
55 People with tuberculosis starting treatment |
Milk thistle fruit extract (silymarin), capsules or tablets (not tea) fruit extract Not shown on this page 4 weeks · vs placebo |
Liver injury occurred in 1 of 27 people on silymarin and 9 of 28 on placebo. Median ALT at week 4 was not significantly different (P = 0.455). The authors call for larger trials. 1/27 vs 9/28 developed liver injury Methods, limits and fundingOutcomes: Drug-related liver injury, liver enzymes Limitations: Small trial; 55 of the 70 planned people enrolled. Funding and conflicts: Registered NCT01800487. Read: abstract |
| Mengs 2012 Legalon® SIL: the antidote of choice in patients with acute hepatotoxicity from amatoxin poisoning. Curr Pharm Biotechnol · PMID 22352731 · DOI |
Review |
People with mushroom (amatoxin) poisoning | Intravenous silibinin (a branded hospital medicine) purified silibinin Not shown on this page hospital treatment |
The review says there are no controlled studies for ethical reasons. From uncontrolled reports of nearly 1,500 cases it says death was under 10 percent with the silibinin medicine and over 20 percent with penicillin or the combination. It describes silibinin blocking the toxin's re-entry into liver cells. Under 10 percent vs over 20 percent (uncontrolled reports) Methods, limits and fundingOutcomes: Mortality Limitations: Uncontrolled data; the title names a branded product; funding not stated in the abstract, so a link to the maker cannot be ruled out. Read: abstract |
| NCBI PubChem 2026 PubChem PUG REST compound look-ups for silymarin, silibinin, silybin B, isosilybin A/B, silychristin, silydianin, taxifolin and other constituents PubChem (database, accessed 2026-10-24) · Source |
Database record n/a |
n/a | n/a |
CIDs were retrieved by compound name and checked against the returned formula: silymarin 5213, silibinin 31553, silybin B 1548994, isosilybin A 11059920, isosilybin B 10885340, silychristin 441764, silydianin 11982272, taxifolin 439533, silipide 6450536. PubChem has several entries for silybin/silibinin with different stereochemistry; no separate CID for silybin A alone could be confirmed by name. Methods, limits and fundingOutcomes: Compound identifiers and formulas Limitations: Name-based lookup; some entries are mixtures or do not state their 3D shape. Read: summary-only |
| National Center for Complementary and Integrative Health (NIH) 2025 Milk Thistle: Usefulness and Safety (NCCIH Herbs at a Glance) NCCIH web page (last updated February 2025) · Source |
Authoritative guidance |
General public | Milk thistle extract (silymarin) fruit (seed) |
Re-read 2026-10-25. Says there is not enough high-quality evidence for firm conclusions. A small number of studies suggest milk thistle extracts may help control blood sugar in type 2 diabetes, mostly in Middle Eastern countries. Liver disease trial results are conflicting or too limited; two NIH-funded trials (hepatitis C; NASH) showed no benefit from the extract silymarin. Unclear for breast milk production. Safety: appears well tolerated by mouth; most common effects are bloating, nausea and gas; poor product quality has been reported (silymarin far from label, pesticides, microbes, mycotoxins); may cause allergic reactions, particularly in people allergic to ragweed, chrysanthemum, marigold or daisy; talk to a health provider about medicines; little is known about pregnancy or breastfeeding. Methods, limits and fundingOutcomes: Safety summary Limitations: General summary; gives no frequencies or named drug interactions. Read: full-text |
| Navarro 2019 Silymarin in non-cirrhotics with non-alcoholic steatohepatitis: A randomized, double-blind, placebo controlled trial. PLoS One · PMID 31536511 · DOI |
Controlled trial |
78 Adults with fatty liver disease with inflammation (NASH) confirmed by biopsy |
Milk thistle fruit extract (silymarin), capsules or tablets (not tea) (standardised product, two strengths) fruit extract Not shown on this page 48 weeks · vs placebo |
Similar numbers improved on silymarin (15 and 19 percent) and placebo (12 percent); P = 0.79. The authors say silymarin showed no benefit in the main analysis and was well tolerated. Many people did not meet the biopsy entry rules, so the question remains open. 15 or 19 percent vs 12 percent on placebo; P = 0.79 Methods, limits and fundingOutcomes: Improvement in liver biopsy score; side effects Limitations: Small; 63 percent did not meet entry biopsy criteria on central review. Funding and conflicts: Public funding (NIH) listed; the product was supplied under a brand name; registered NCT00680407. Read: abstract |
| Pickova 2020 Presence of Mycotoxins in Milk Thistle (Silybum marianum) Food Supplements: A Review. Toxins (Basel) · PMID 33302488 · DOI |
Review n/a |
Review of mycotoxins in milk thistle supplements | Milk thistle supplements fruit extract products Not shown on this page |
Names mycotoxins most often found in milk thistle supplements, including alternariol, beauvericin, deoxynivalenol, enniatins, HT-2, T-2, tentoxin and zearalenone. Says these are not covered by EU legislation for these supplements. n/a Methods, limits and fundingOutcomes: Mycotoxin findings Limitations: Review of supplements, not tea. Read: abstract |
| Piscitelli 2002 Effect of milk thistle on the pharmacokinetics of indinavir in healthy volunteers. Pharmacotherapy · PMID 12013352 · DOI |
Clinical trial |
10 10 healthy volunteers |
Milk thistle fruit extract (silymarin), capsules or tablets (not tea) with the HIV drug indinavir fruit extract Not shown on this page 3 weeks · vs own measurements before treatment |
Total indinavir exposure fell by 9 percent (not significant). The trough (lowest) level fell by 25 percent (significant). The authors concluded it should not interfere with indinavir therapy at usual amounts. AUC -9 percent; trough -25 percent Methods, limits and fundingOutcomes: Indinavir blood levels Limitations: Only indinavir, an older drug; ten healthy people. Read: abstract |
| Planas-Vinos 2025 Anaphylaxis Induced by Milk Thistle (Silybum marianum) Seed Ingestion: A Case Report. J Investig Allergol Clin Immunol · PMID 40036083 · DOI |
Case report |
1 One person with anaphylaxis after eating milk thistle seed |
Milk thistle seed eaten seed Not shown on this page single exposure |
Title only: an anaphylaxis case after eating milk thistle seed. No abstract is available, so no details are used. Methods, limits and fundingOutcomes: Allergic reaction Limitations: Title read only. Read: title-only |
| Quan 2026 Insights into Antioxidant Activity and Trace Element Distribution of Aqueous Extract of Silybum marianum Seeds. Molecules · PMID 41900133 · DOI |
Lab in vitro |
A boiling-water decoction of milk thistle seeds in the lab | Water extract of the seeds seed Not shown on this page |
The lab separated silymarin parts from the decoction and measured nine metal elements and a free-radical test. Iron, copper, manganese and zinc were mostly free ions. The abstract gives no amount of silymarin. The authors propose that seed tea could supply trace elements and silymarin; this is their suggestion and is not tested in people. n/a Methods, limits and fundingOutcomes: Trace elements and antioxidant activity Limitations: Lab study. No silymarin amount per cup is given in the abstract. Read: abstract |
| Que 2024 Evaluation of the effect of herbal agents as management of radiodermatitis in breast cancer patients: A systematic review and meta-analysis. Jpn J Nurs Sci · PMID 37816677 · DOI |
Meta-analysis |
1994 Women with breast cancer having radiotherapy (16 studies; 10 trials tested calendula, silymarin or aloe vera) |
Silymarin applied to skin among other herbal agents (topical, not a drink) fruit extract Not shown on this page varied · vs standard care or placebo |
The authors say silymarin showed positive effects on radiation skin damage, while calendula and aloe vera lacked enough evidence. They call for more trials. Not pooled for silymarin in the abstract Methods, limits and fundingOutcomes: Radiation skin reaction Limitations: Topical use, so not applicable to a tea; the abstract gives no numbers for silymarin. Read: abstract |
| Rajnarayana 2004 Study on the influence of silymarin pretreatment on metabolism and disposition of metronidazole. Arzneimittelforschung · PMID 15038460 · DOI |
Clinical trial |
12 12 healthy volunteers |
Milk thistle fruit extract (silymarin), low-strength capsules (not tea) taken with the antibiotic metronidazole fruit extract Not shown on this page 9 days · vs own measurements before treatment |
Silymarin raised clearance of metronidazole and its main product by about 30 percent, with lower peak and total levels. The authors suggest it may switch on a gut transporter and the enzyme CYP3A4. Clearance up 29.5 percent Methods, limits and fundingOutcomes: Metronidazole clearance Limitations: Twelve healthy people; one study. Read: abstract |
| Rambaldi 2007 Milk thistle for alcoholic and/or hepatitis B or C virus liver diseases. Cochrane Database Syst Rev · PMID 17943794 · DOI |
Systematic review |
1088 People with alcohol-related liver disease and/or hepatitis B or C (18 trials) |
Milk thistle fruit extract (silymarin), capsules or tablets (not tea) fruit extract Not shown on this page varied · vs placebo or no treatment |
No clear effect on death (RR 0.78) or on complications of liver disease (RR 0.95) or liver tissue. Liver-related death was lower across all trials (RR 0.50) but not in the higher-quality trials (RR 0.57, CI 0.28 to 1.19). No significant rise in side effects (RR 0.83). Only 28.6 percent of trials had high-quality methods. Mortality RR 0.78 (0.53 to 1.15) Methods, limits and fundingOutcomes: Death, complications, liver tissue changes, side effects Limitations: Cochrane review from 2007; trials mostly low quality; extracts, not tea. Funding and conflicts: Cochrane reviews are independent of industry. Read: abstract |
| Selc 2024 Novel Strategies Enhancing Bioavailability and Therapeutical Potential of Silibinin for Treatment of Liver Disorders. Drug Des Devel Ther · PMID 39444787 · DOI |
Review review |
Review of silibinin and ways to improve its absorption | Silibinin compound Not shown on this page |
Describes the silibinin molecule as insoluble in water with poor absorption in the body, so makers build new forms (a water-soluble salt, a fat complex). Most of the evidence discussed is lab and animal work. n/a Methods, limits and fundingOutcomes: Bioavailability Limitations: Review; not about tea. Read: abstract |
| Soleimani 2019 Safety and toxicity of silymarin, the major constituent of milk thistle extract: An updated review. Phytother Res · PMID 31069872 · DOI |
Review |
Review of silymarin safety in animals and people | Milk thistle fruit extract (silymarin), capsules or tablets (not tea) fruit extract Not shown on this page varied |
No major toxicity in animals. Silymarin was well tolerated in people, with nausea and diarrhoea sometimes reported. It showed mutagenic activity in some bacteria with liver enzymes, but silybin, silydianin and silychristin were not toxic to cells in the test. The review says caution in pregnancy and with drugs that have a narrow safety margin. n/a Methods, limits and fundingOutcomes: Safety and toxicity Limitations: Narrative review; about extracts. Read: abstract |
| Soleymani 2022 The effects of Silymarin on the features of cardiometabolic syndrome in adults: A systematic review and meta-analysis. Phytother Res · PMID 35016260 · DOI |
Meta-analysis |
Adults with features of cardiometabolic syndrome (11 trials) | Milk thistle fruit extract (silymarin), capsules or tablets (not tea) fruit extract Not shown on this page varied · vs placebo |
Lower fasting glucose, total cholesterol, triglycerides and LDL, and higher HDL; BMI did not change. The authors note high heterogeneity and the need for better trials. Fasting glucose -17.96 mg/dL; total cholesterol -17.46 mg/dL (glucose -32.91 to -3.02) Methods, limits and fundingOutcomes: Blood sugar, HbA1c, cholesterol, blood fats, BMI Limitations: High heterogeneity (I2 up to 93 percent); this conflicts with the 2016 diabetes review, which found no cholesterol effect. Read: abstract |
| Sridar 2004 Silybin inactivates cytochromes P450 3A4 and 2C9 and inhibits major hepatic glucuronosyltransferases. Drug Metab Dispos · PMID 15155549 · DOI |
Lab in vitro |
Purified human enzymes in a test tube | Silybin (a milk thistle compound) compound Not shown on this page |
Silybin switched off CYP3A4 and CYP2C9 and blocked UGT enzymes in test-tube conditions. The authors advise care with drugs cleared by these enzymes. Whether this happens in people is unknown. n/a Methods, limits and fundingOutcomes: Enzyme inactivation Limitations: Test tube only. Read: abstract |
| Tan 2022 Amanitin intoxication: effects of therapies on clinical outcomes - a review of 40 years of reported cases. Clin Toxicol (Phila) · PMID 36129244 · DOI |
Systematic review |
877 People poisoned by amanitin-containing mushrooms (death cap and relatives); 131 publications, case reports and series |
Silibinin given into a vein in hospital (a medicine, not a tea), compared with other hospital treatments purified silibinin Not shown on this page hospital treatment · vs supportive care or other antidotes |
Overall 84 percent survived. Supportive care only: 59 percent. With silibinin alone: 90 percent. But in confirmed poisonings the authors found no statistical difference between treatments; they say silibinin or penicillin seem linked with better survival. Survival 90 percent with silibinin vs 59 percent supportive care only (OR 6.40, 3.14 to 13.04) Methods, limits and fundingOutcomes: Survival Limitations: Case reports and series, not trials; sicker people may be treated differently. Read: abstract |
| Tao 2019 Prophylactic Therapy of Silymarin (Milk Thistle) on Antituberculosis Drug-Induced Liver Injury: A Meta-Analysis of Randomized Controlled Trials. Can J Gastroenterol Hepatol · PMID 30733935 · DOI |
Meta-analysis |
1198 People starting anti-tuberculosis drugs (5 randomised trials) |
Milk thistle fruit extract (silymarin), capsules or tablets (not tea) fruit extract Not shown on this page about 4 weeks and longer · vs placebo |
Liver injury from the tuberculosis drugs was less common at week 4 with silymarin (RR 0.33). Liver tests were slightly better. Side effects were similar to placebo. RR 0.33 for liver injury at week 4 (0.15 to 0.75) Methods, limits and fundingOutcomes: Drug-related liver injury, liver tests, side effects Limitations: Five trials; follow-up short; extracts, not tea. Read: abstract |
| Tournas 2013 Fungal profiles in various milk thistle botanicals from US retail. Int J Food Microbiol · PMID 23624536 · DOI |
Other n/a |
US retail milk thistle products | Whole seeds, cut herb, seed tea bags, extracts, capsules and soft gels seed and extracts Not shown on this page |
A high share of samples carried fungi (up to 5.60 log10 cfu/g). Whole seeds had the most, then cut herb. No live fungi were recovered from milk thistle seed tea bags, liquid extracts, capsules or soft gels. Potentially toxin-producing moulds were isolated. n/a Methods, limits and fundingOutcomes: Mould counts and species Limitations: Live mould counts only; toxins were not measured here; tea bags were few. Read: abstract |
| Tvrdý 2021 Systematic review of pharmacokinetics and potential pharmacokinetic interactions of flavonolignans from silymarin. Med Res Rev · PMID 33587317 · DOI |
Systematic review review |
Systematic review of how the body handles silymarin compounds | Silymarin flavonolignans extract Not shown on this page |
Two reasons for poor absorption: rapid attachment of sugar or sulphate groups in gut and liver, and pumping back into the gut. Only about 1 to 5 percent of a dose leaves in urine. Many lab effects on drug enzymes use concentrations too high to matter in real life. Most human studies showed no interactions; more were seen in animals. n/a Methods, limits and fundingOutcomes: Absorption, breakdown, interactions Limitations: Review. Read: abstract |
| Voroneanu 2016 Silymarin in Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. J Diabetes Res · PMID 27340676 · DOI |
Meta-analysis |
270 People with type 2 diabetes (5 randomised trials) |
Milk thistle fruit extract (silymarin), capsules or tablets (not tea) fruit extract Not shown on this page varied · vs placebo |
Fasting blood sugar fell by about 27 mg/dL and HbA1c by about 1 point compared with control. No effect on cholesterol and blood fats. The authors say quality was low, trials differed a lot, and no recommendation can be made. Fasting glucose -26.86 mg/dL; HbA1c -1.07 (glucose -35.42 to -18.30; HbA1c -1.73 to -0.40) Methods, limits and fundingOutcomes: Fasting blood sugar, HbA1c, cholesterol Limitations: Small trials, low quality, high heterogeneity. Read: abstract |
| Wang 2025 Silymarin for adults with metabolic dysfunction-associated steatotic liver disease. Cochrane Database Syst Rev · PMID 40552569 · DOI |
Systematic review |
2069 Adults with fatty liver disease (MASLD) in 17 trials |
Milk thistle fruit extract (silymarin), capsules or tablets (not tea) or silymarin complexes fruit extract Not shown on this page 4 to 48 weeks · vs placebo, no treatment or other treatments |
Silymarin alone may lower ALT by about 7 U/L compared with placebo or no treatment (very low certainty). Silymarin bound to other ingredients showed no clear change. Little to no difference in serious side effects (low certainty). No trial reported death or quality of life. The authors say benefits and harms are unclear. ALT mean difference -7.21 U/L (silymarin alone vs placebo or nothing) (-10.62 to -3.80) Methods, limits and fundingOutcomes: Serious side effects, death, quality of life, liver enzymes Limitations: Certainty low to very low: small trials, risk of bias, results differ a lot between trials. Extracts, not tea. Funding and conflicts: Cochrane review, no dedicated funding. Read: abstract |
| Yin 2025 Effects of silymarin on insulin resistance and sensitivity: A systematic review and meta-analysis of randomized controlled trials. Diabetes Res Clin Pract · PMID 39855603 · DOI |
Meta-analysis |
673 Adults with insulin resistance or related conditions (6 trials from Iran, Egypt, Italy) |
Milk thistle fruit extract (silymarin), capsules or tablets (not tea) fruit extract Not shown on this page at least 4 weeks · vs placebo |
HOMA-IR improved slightly overall (WMD -2.29; CI -4.55 to -0.03, borderline) but fasting insulin did not change. The effect was seen in type 2 diabetes but not in fatty liver. The authors say evidence is limited. HOMA-IR WMD -2.29 (-4.55 to -0.03) Methods, limits and fundingOutcomes: Insulin resistance (HOMA-IR), fasting insulin Limitations: Six trials; results borderline. Read: abstract |
| de Avelar 2017 Effect of silymarin on biochemical indicators in patients with liver disease: Systematic review with meta-analysis. World J Gastroenterol · PMID 28785154 · DOI |
Systematic review |
Adults with liver disease; 6 trials in the pooled analysis (17 in the review) | Milk thistle fruit extract (silymarin), capsules or tablets (not tea) alone or with other nutrients fruit extract Not shown on this page varied · vs placebo or control |
ALT and AST fell by tiny amounts that the authors say had no clinical relevance. GGT did not change. The trials were very different and of low quality. ALT -0.26 IU/mL; AST -0.53 IU/mL (ALT -0.46 to -0.07; AST -0.74 to -0.32) Methods, limits and fundingOutcomes: ALT, AST and GGT liver blood tests Limitations: Low methodological quality, high heterogeneity. Read: abstract |
| van Erp 2005 Effect of milk thistle (Silybum marianum) on the pharmacokinetics of irinotecan. Clin Cancer Res · PMID 16278402 · DOI |
Clinical trial |
6 6 people with cancer given the chemotherapy drug irinotecan |
Milk thistle fruit extract (silymarin), capsules or tablets (not tea) with irinotecan fruit extract Not shown on this page 14 days · vs own measurements |
No significant effect on irinotecan clearance. Silybin blood levels were too low to affect the enzymes involved, so the authors judged an interaction unlikely. Clearance 31.2 vs 25.4 vs 25.6 L/h; P = 0.16 Methods, limits and fundingOutcomes: Irinotecan clearance and breakdown products Limitations: Six patients; one drug. Funding and conflicts: Public funding (NIH) listed. Read: abstract |
What we do not know yet
- No human trial of milk thistle tea was found.
- The amount of silymarin in a cup of tea has not been measured.
- No survey of mould toxins, pesticides or metals in milk thistle tea bags was found.
- No study tests the tea with medicines, in pregnancy or in children.
- LiverTox and LactMed were read as summaries only.
How new research is added
New studies are found by a saved PubMed search and are placed in a review queue. A person reads each one before it is added.
Lab markers
What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".
Metabolic 3
Fasting blood sugar and HbA1c
Lowered in trials
Blood sugar after an overnight fast, and HbA1c, which reflects average blood sugar over 2 to 3 months.
Low certaintyResults and what it means
Why it was measured
The usual way to follow diabetes.
Statistical vs. clinical meaning
Lower in small trials of extract; not tested with tea.
Safety implication
Low blood sugar is possible in theory with diabetes medicines.
| Study | Result | People | Product |
|---|---|---|---|
| 37 | Fasting glucose -26.86 mg/dL; HbA1c -1.07 | 5 trials, 270 people with type 2 diabetes | Silymarin extract |
Total cholesterol and triglycerides
Mixed results in trials
Fats carried in the blood.
Mixed findingsResults and what it means
Why it was measured
Linked to heart disease risk.
Statistical vs. clinical meaning
The two analyses disagree.
Safety implication
None directly.
Insulin resistance (HOMA-IR)
Lowered in trials
A calculation from fasting sugar and insulin that estimates how well the body responds to insulin.
Low certaintyOther 1
Liver enzymes ALT and AST
Lowered in trials
Enzymes that leak into the blood when liver cells are injured. Higher means more irritation or injury.
Very low certaintyResults and what it means
Why it was measured
They are the usual blood tests for liver irritation.
Statistical vs. clinical meaning
Small drops in a blood test; the test is not a symptom or an outcome.
Safety implication
A rise in liver enzymes or yellow skin or eyes needs a doctor.
| Study | Result | People | Product |
|---|---|---|---|
| 38 | Silymarin alone may lower ALT by about 7 U/L vs placebo or nothing (CI -10.62 to -3.80), very low certainty | 6 trials, 409 people with fatty liver | Silymarin extract |
| 40 | ALT and AST lower by tiny amounts, without clinical relevance | 6 trials, liver disease | Silymarin |
| 9 | ALT fall not different from placebo (P = 0.75) | 154 people with hepatitis C | Silymarin extract |
Safety
What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.
Main points to know 7
- Allergy: avoid with an allergy to ragweed or the daisy family. Milk thistle is in the daisy family (Asteraceae). NCCIH says it may cause allergic reactions, especially in people allergic to related plants such as ragweed, chrysanthemum, marigold and daisy. The EU monograph lists allergy to milk thistle or other Asteraceae plants as a contraindication. A 2025 case report describes anaphylaxis after eating milk thistle seed (title read only). We found no study measuring how often ragweed-allergic people react. Authoritative guidance 20 5 24
- Pregnancy and breastfeeding: the EU does not recommend it. The EU monograph says safety in pregnancy and lactation has not been established and use is not recommended. NCCIH says little is known. One mouse study found no early developmental changes but some adult behaviour differences. LactMed (summary) says silymarin was not found in breast milk in measurable amounts and an infant effect is unlikely. No study of the tea was found. Authoritative guidance 5 20 3 4
- Medicines: lab work suggests a risk; human studies of extract mostly found little. Lab studies show silybin can block drug-processing enzymes (CYP3A4, CYP2C9, UGT). In small human studies of extract, enzyme activity did not change, but a few drugs changed a little. The EU monograph lists no reported interactions. Studies used extracts, not tea, so the effect of a cup is unknown. Ask a pharmacist if you take warfarin, statins, diabetes medicine, tamoxifen, raloxifene, chemotherapy or HIV medicine. Pharmacological theory 32 12 36 5
- Blood sugar medicine: a possible add-on effect. Silymarin extract lowered blood sugar in small trials of type 2 diabetes. In theory the effects could add up with diabetes medicine. No study of low blood sugar with milk thistle plus a diabetes drug was found. Pharmacological theory 37 20
- Liver disease needs a doctor. Milk thistle is not a treatment for liver disease. The EU monograph says to see a doctor right away if the skin or eyes turn yellow or urine or stool changes colour, and to see a doctor if symptoms last over two weeks. LiverTox says milk thistle has not been implicated in liver injury (opening statement only). Authoritative guidance 5 16
- Mild stomach upset is the usual side effect. NCCIH says milk thistle by mouth appears well tolerated, with bloating, nausea and gas the most common effects. A 2007 Cochrane review (18 trials, 1,088 people) found no significant rise in side effects (RR 0.83). Mostly extract trials, mostly in people with liver disease. Systematic review 20 28 30
- Tea quality is not measured. Surveys of supplements (not tea) found silymarin far from the label, mould toxins, pesticides and microbes. A US study found no live moulds in seed tea bags but many in whole seeds. No survey of tea bags for toxins or metals was found. Other 7 35 22
Side effects 3
| Effect | How often | Severity and recovery | Evidence |
|---|---|---|---|
| Bloating, nausea, gas, diarrhoea Seen with extracts; tea not measured. | NCCIH lists these as the most common; EU monograph: frequency not known | mild Reversible | Authoritative guidance 20 5 |
| Dry mouth, headache | EU monograph: not known | mild Reversible | Authoritative guidance 5 |
| Allergic reaction, from rash to anaphylaxis Highest risk with daisy-family allergy. | Not given | variable, can be severe Usually reversible; anaphylaxis is an emergency | Authoritative guidance 20 5 24 |
Liver
LiverTox says milk thistle has not been implicated in causing liver injury (opening statement only; the likelihood score was not opened). The EU assessment says its drug-safety database lists no milk-thistle-related liver events, which is a statement about reports received, not a rate. A survey of supplements found contamination, which the authors suggest may be linked with supplement liver injury; this is their suggestion, not proof. No case from milk thistle tea was found. 16 5 7
How often. No rate can be calculated.
Monitoring. Seek a doctor if skin or eyes turn yellow, urine is dark or stools pale (EU monograph).
This is a safety connection. It is not evidence that Milk Thistle Tea supports liver health.
Medicines and supplements 6
| With | Why it matters | Importance | Evidence | What to do |
|---|---|---|---|---|
| Medicines cleared by liver enzymes CYP3A4 or CYP2C9 (for example warfarin and many statins) prescription | Silybin inactivated these enzymes in test-tube work. In 9 healthy volunteers a standardised extract did not significantly change four major enzymes, including these. | Human probe studies found little effect, but they were small and used extract. No study with warfarin or a statin was found. Tea not tested. | Pharmacological theory Low certainty 32 12 36 | Tell your prescriber or pharmacist you drink milk thistle tea, especially with warfarin. |
| Diabetes medicines prescription | Silymarin extract lowered blood sugar in a meta-analysis of 5 trials (270 people). | A possible add-on effect; no study of low blood sugar was found. | Pharmacological theory Very low certainty 37 20 | If you use diabetes medicine, check blood sugar as your care team advises and tell them. |
| Tamoxifen and raloxifene prescription | In rats silybinin raised tamoxifen exposure by 40 to 71 percent. In lab work silybin A and B strongly slowed gut breakdown of raloxifene, and a model predicted a 4- to 5-fold rise. | Rat and lab evidence only. No human data. | Animal research Very low certainty 13 11 | Ask your cancer or breast team before adding milk thistle. |
| Chemotherapy (irinotecan studied) prescription | In 6 cancer patients milk thistle did not change irinotecan clearance significantly; silybin blood levels were judged too low to affect the enzymes. | Reassuring but tiny. Chemotherapy has narrow safety margins. | Clinical trial Low certainty 41 | Never add a supplement during chemotherapy without your oncology team. |
| HIV medicine (indinavir studied; newer medicines not) prescription | In 10 healthy volunteers total indinavir exposure fell 9 percent (not significant) but the trough level fell 25 percent. | Old drug, small study. No study of newer HIV medicines was found. | Clinical trial Low certainty 23 | Check with your HIV clinician or pharmacist first. |
| Metronidazole prescription | In 12 healthy volunteers silymarin increased metronidazole clearance by about 30 percent. | One small study; meaning unknown. | Clinical trial Very low certainty 27 | Ask a pharmacist if you take antibiotics. |
Who should check first 7
| Situation | Advice | Evidence |
|---|---|---|
| Allergy to milk thistle or to daisy-family plants (ragweed, chrysanthemum, marigold, daisy, artichoke, common thistle) | Do not use. The EU lists this as a contraindication. | Authoritative guidance 5 20 |
| Pregnancy | Not recommended: safety not established (EU monograph). | Authoritative guidance 5 20 |
| Breastfeeding | The EU does not recommend it for lack of data. LactMed finds an infant effect unlikely. Talk to a lactation professional. | Authoritative guidance 5 4 |
| Children and teenagers under 18 | Use has not been established (EU monograph). Give only on medical advice. | Authoritative guidance 5 14 |
| Liver disease or unexplained abnormal liver tests | A tea is not a treatment. See a doctor; the EU advises seeing a doctor if symptoms last over two weeks. | Authoritative guidance 5 9 28 |
| Breast, uterine or ovarian cancer, or treatment with tamoxifen or raloxifene | No agency lists this as a contraindication. Ask your treating team first because of the animal and lab findings above. | Animal research 13 11 |
| Medicines with a narrow safety margin (warfarin, chemotherapy, HIV medicine, transplant medicine) | Ask the prescriber or pharmacist first. | Pharmacological theory 30 12 23 41 |
Overdose, product quality and regulators
Summary. Animal tests show low toxicity. The EU says no case of overdose has been reported, and notes that tests of these preparations for reproductive effects, genotoxicity and cancer risk have not been done. One review found silymarin mutagenic in some bacteria tests with liver enzymes, but its main compounds were not toxic to cells. These data cannot rule out rare allergy or effects of contaminated products.
Animal. See the safety review; rodent work found low toxicity.
Human doses studied. Not shown on this page.
High dose or long term signals. No clear signal in the trials read. Long-term safety is not documented in the sources read.
Overdose response. No overdose case is reported (EU).
Genotoxicity. Mixed laboratory findings; EMA did not recommend a list entry for lack of adequate tests.
Quality is a real concern for milk thistle supplements. For tea the picture is thin: a US study found no live moulds in seed tea bags but many in whole seeds, and no tea survey for mould toxins, pesticides or metals was found.
Silymarin content unlike the label. In 26 supplements from the US and Czech markets, silymarin content differed greatly between products and batches, often from the label. 7 20
Mycotoxins and pesticides. All 26 supplements carried mycotoxins, several pesticides and microbes. A review lists the mycotoxins most often found and notes they are not covered by EU law for these supplements. 7 22
Moulds in seed and tea bags. Whole seeds carried the most live fungi, then cut herb. None were recovered from seed tea bags, liquid extracts, capsules or soft gels in that survey. 35
| Body | Action | Date |
|---|---|---|
| European Medicines Agency, Committee on Herbal Medicinal Products (HMPC) (European Union) | Herbal monograph on milk thistle fruit: traditional use only, a herbal tea is a listed form. For symptomatic relief of digestive disorders, a feeling of fullness and indigestion, and to support the liver after serious conditions are ruled out. Contraindicated with hypersensitivity, including to Asteraceae plants. Not recommended under 18, or in pregnancy and lactation. No interactions reported. See a doctor if symptoms last over 2 weeks or if yellow skin or eyes appear. source | 2018-06-05 |
| NCCIH (US National Institutes of Health) (United States) | Not enough high-quality evidence for firm conclusions. Appears well tolerated by mouth; may cause allergic reactions; quality concerns; talk to a provider about medicines; little known in pregnancy and breastfeeding. Dietary supplements are not approved by the FDA before sale. source | Page last updated February 2025 |
When to get medical help
- Swelling of lips, tongue or face, hives, wheezing or trouble breathing: call emergency services (US 911). Anaphylaxis has been reported with milk thistle seed.
- Yellow skin or eyes, dark urine, pale stools or severe itching: stop and get medical care the same day.
- A spreading itchy rash, or persistent vomiting or diarrhoea: stop and see a doctor.
- New bleeding or bruising if you take warfarin, very low blood sugar if you take diabetes medicine, or new side effects on other medicines: call your prescriber or pharmacist promptly.
- If you may have eaten a poisonous wild mushroom, call poison control (US 1-800-222-1222) or emergency services at once. Milk thistle tea is not a treatment.
Stop using the product and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.
General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.
Frequently asked questions
Does milk thistle tea help the liver?
Is there much silymarin in a cup of milk thistle tea?
Nobody has shown how much. A 2024 review describes silibinin, a main compound, as insoluble in water with poor absorption. A 2026 lab study of a boiling-water seed decoction did not give a silymarin amount in its abstract. So a cup may carry little, and extract results should not be assumed for tea.
Does milk thistle tea contain caffeine?
None of the sources we read report caffeine in milk thistle tea. The plant is not a true tea plant (Camellia), so caffeine would not be expected, but that is general background and was not tested. Blends with black or green tea can add caffeine, so read the label.
Who should not drink milk thistle tea?
Is milk thistle tea safe in pregnancy or breastfeeding?
Can milk thistle interact with my medicines?
Possibly. In lab work silybin blocks drug-processing enzymes, but small human studies of extract mostly found little effect. Rat and lab work suggest ask-first for tamoxifen and raloxifene. Studies were of extract, not tea. Ask a pharmacist if you take warfarin, statins, diabetes medicine, chemotherapy or HIV medicine.
Does milk thistle lower blood sugar?
Can milk thistle tea treat death-cap mushroom poisoning?
Is milk thistle tea the same as milk thistle capsules?
Does milk thistle tea help breastfeeding mothers make more milk?
Can milk thistle damage the liver?
LiverTox's opening statement says milk thistle has not been implicated in liver injury, and no case from the tea was found. Supplement surveys found mould toxins and pesticides, which authors link to possible harm; that is their suggestion. See a doctor for yellow skin or eyes, dark urine or pale stools.
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Editorial transparency
- Written by
- AlternativeMed editorial team. Research compiled with AI assistance, then checked against PubMed records.
- Medical review
- None. This page has not been reviewed by a physician or pharmacist.
- First published
- 2026-10-25
- Last substantive update
- 2026-10-25
- How we research
- We read the abstracts of 32 PubMed papers (one more was title-only), re-opened the NCCIH page and the EU monograph, and used earlier readings of LiverTox, LactMed and GBIF. The LiverTox and LactMed records were read as summaries only.
- How we rate evidence
- See "How we rate evidence" in the Evidence tab.
- Independence
- No product is promoted on this page. No affiliate links are shown.
Sources 41
Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.
- Abenavoli L, Izzo AA, Milić N et al.. Milk thistle (Silybum marianum): A concise overview on its chemistry, pharmacological, and nutraceutical uses in liver diseases.. Phytother Res. 2018. PMID 30080294. DOI 10.1002/ptr.6171. (abstract)
- AlternativeMed editorial search. Search for human trials of milk thistle tea (PubMed and Europe PMC phrase searches, repeated for this page). Search record. 2026. (summary-only)
- Barbosa CC, Nishimura AN, Santos MLD et al.. Silymarin administration during pregnancy and breastfeeding: evaluation of initial development and adult behavior of mice.. Neurotoxicology. 2020. PMID 32084436. DOI 10.1016/j.neuro.2020.02.008. (abstract)
- Drugs and Lactation Database (NICHD/NIH). Milk Thistle (LactMed). LactMed, updated 15 March 2026. 2026. PMID 30000830. (summary-only)
- European Medicines Agency, Committee on Herbal Medicinal Products (HMPC). European Union herbal monograph on Silybum marianum (L.) Gaertn., fructus (EMA/HMPC/294187/2013). EMA monograph, adopted 5 June 2018. 2018. (partial-text)
- European Medicines Agency, Committee on Herbal Medicinal Products (HMPC). Assessment report on Silybum marianum (L.) Gaertn., fructus (EMA/HMPC/294188/2013). EMA assessment report, 78 pages, 5 June 2018. 2018. (summary-only)
- Fenclova M, Novakova A, Viktorova J et al.. Poor chemical and microbiological quality of the commercial milk thistle-based dietary supplements may account for their reported unsatisfactory and non-reproducible clinical outcomes.. Sci Rep. 2019. PMID 31366891. DOI 10.1038/s41598-019-47250-0. (abstract)
- Foong SC, Tan ML, Foong WC et al.. Oral galactagogues (natural therapies or drugs) for increasing breast milk production in mothers of non-hospitalised term infants.. Cochrane Database Syst Rev. 2020. PMID 32421208. DOI 10.1002/14651858.CD011505.pub2. (abstract)
- Fried MW, Navarro VJ, Afdhal N et al.. Effect of silymarin (milk thistle) on liver disease in patients with chronic hepatitis C unsuccessfully treated with interferon therapy: a randomized controlled trial.. JAMA. 2012. PMID 22797645. DOI 10.1001/jama.2012.8265. (abstract)
- GBIF Secretariat. GBIF Backbone Taxonomy: Silybum marianum (L.) Gaertn., species key 3145214 (with synonyms, vernacular names and name matches for look-alike species). GBIF (database, accessed 2026-10-24). 2026. (summary-only)
- Gufford BT, Chen G, Vergara AG et al.. Milk Thistle Constituents Inhibit Raloxifene Intestinal Glucuronidation: A Potential Clinically Relevant Natural Product-Drug Interaction.. Drug Metab Dispos. 2015. PMID 26070840. DOI 10.1124/dmd.115.065086. (abstract)
- Kawaguchi-Suzuki M, Frye RF, Zhu HJ et al.. The effects of milk thistle (Silybum marianum) on human cytochrome P450 activity.. Drug Metab Dispos. 2014. PMID 25028567. DOI 10.1124/dmd.114.057232. (abstract)
- Kim CS, Choi SJ, Park CY et al.. Effects of silybinin on the pharmacokinetics of tamoxifen and its active metabolite, 4-hydroxytamoxifen in rats.. Anticancer Res. 2010. PMID 20150620. (abstract)
- Ladas EJ, Kroll DJ, Oberlies NH et al.. A randomized, controlled, double-blind, pilot study of milk thistle for the treatment of hepatotoxicity in childhood acute lymphoblastic leukemia (ALL).. Cancer. 2010. PMID 20014183. DOI 10.1002/cncr.24723. (abstract)
- Li S, Duan F, Li S et al.. Administration of silymarin in NAFLD/NASH: A systematic review and meta-analysis.. Ann Hepatol. 2024. PMID 38579127. DOI 10.1016/j.aohep.2023.101174. (abstract)
- LiverTox, NIDDK/NIH. Milk Thistle (LiverTox). LiverTox: Clinical and Research Information on Drug-Induced Liver Injury, 21 January 2020. 2020. PMID 31644124. (summary-only)
- Luangchosiri C, Thakkinstian A, Chitphuk S et al.. A double-blinded randomized controlled trial of silymarin for the prevention of antituberculosis drug-induced liver injury.. BMC Complement Altern Med. 2015. PMID 26400476. DOI 10.1186/s12906-015-0861-7. (abstract)
- Mengs U, Pohl RT, Mitchell T. Legalon® SIL: the antidote of choice in patients with acute hepatotoxicity from amatoxin poisoning.. Curr Pharm Biotechnol. 2012. PMID 22352731. DOI 10.2174/138920112802273353. (abstract)
- NCBI PubChem. PubChem PUG REST compound look-ups for silymarin, silibinin, silybin B, isosilybin A/B, silychristin, silydianin, taxifolin and other constituents. PubChem (database, accessed 2026-10-24). 2026. (summary-only)
- National Center for Complementary and Integrative Health (NIH). Milk Thistle: Usefulness and Safety (NCCIH Herbs at a Glance). NCCIH web page (last updated February 2025). 2025. (full-text)
- Navarro VJ, Belle SH, D'Amato M et al.. Silymarin in non-cirrhotics with non-alcoholic steatohepatitis: A randomized, double-blind, placebo controlled trial.. PLoS One. 2019. PMID 31536511. DOI 10.1371/journal.pone.0221683. (abstract)
- Pickova D, Ostry V, Toman J et al.. Presence of Mycotoxins in Milk Thistle (Silybum marianum) Food Supplements: A Review.. Toxins (Basel). 2020. PMID 33302488. DOI 10.3390/toxins12120782. (abstract)
- Piscitelli SC, Formentini E, Burstein AH et al.. Effect of milk thistle on the pharmacokinetics of indinavir in healthy volunteers.. Pharmacotherapy. 2002. PMID 12013352. DOI 10.1592/phco.22.8.551.33205. (abstract)
- Planas-Vinos M, Sala-Cunill A, Luengo O et al.. Anaphylaxis Induced by Milk Thistle (Silybum marianum) Seed Ingestion: A Case Report.. J Investig Allergol Clin Immunol. 2025. PMID 40036083. DOI 10.18176/jiaci.1057. (title-only)
- Quan L, Wang YX, Cai XL et al.. Insights into Antioxidant Activity and Trace Element Distribution of Aqueous Extract of Silybum marianum Seeds.. Molecules. 2026. PMID 41900133. DOI 10.3390/molecules31061034. (abstract)
- Que S, Ma X, Yang T et al.. Evaluation of the effect of herbal agents as management of radiodermatitis in breast cancer patients: A systematic review and meta-analysis.. Jpn J Nurs Sci. 2024. PMID 37816677. DOI 10.1111/jjns.12559. (abstract)
- Rajnarayana K, Reddy MS, Vidyasagar J et al.. Study on the influence of silymarin pretreatment on metabolism and disposition of metronidazole.. Arzneimittelforschung. 2004. PMID 15038460. DOI 10.1055/s-0031-1296944. (abstract)
- Rambaldi A, Jacobs BP, Gluud C. Milk thistle for alcoholic and/or hepatitis B or C virus liver diseases.. Cochrane Database Syst Rev. 2007. PMID 17943794. DOI 10.1002/14651858.CD003620.pub3. (abstract)
- Selc M, Macova R, Babelova A. Novel Strategies Enhancing Bioavailability and Therapeutical Potential of Silibinin for Treatment of Liver Disorders.. Drug Des Devel Ther. 2024. PMID 39444787. DOI 10.2147/DDDT.S483140. (abstract)
- Soleimani V, Delghandi PS, Moallem SA et al.. Safety and toxicity of silymarin, the major constituent of milk thistle extract: An updated review.. Phytother Res. 2019. PMID 31069872. DOI 10.1002/ptr.6361. (abstract)
- Soleymani S, Ayati MH, Mansourzadeh MJ et al.. The effects of Silymarin on the features of cardiometabolic syndrome in adults: A systematic review and meta-analysis.. Phytother Res. 2022. PMID 35016260. DOI 10.1002/ptr.7364. (abstract)
- Sridar C, Goosen TC, Kent UM et al.. Silybin inactivates cytochromes P450 3A4 and 2C9 and inhibits major hepatic glucuronosyltransferases.. Drug Metab Dispos. 2004. PMID 15155549. DOI 10.1124/dmd.32.6.587. (abstract)
- Tan JL, Stam J, van den Berg AP et al.. Amanitin intoxication: effects of therapies on clinical outcomes - a review of 40 years of reported cases.. Clin Toxicol (Phila). 2022. PMID 36129244. DOI 10.1080/15563650.2022.2098139. (abstract)
- Tao L, Qu X, Zhang Y et al.. Prophylactic Therapy of Silymarin (Milk Thistle) on Antituberculosis Drug-Induced Liver Injury: A Meta-Analysis of Randomized Controlled Trials.. Can J Gastroenterol Hepatol. 2019. PMID 30733935. DOI 10.1155/2019/3192351. (abstract)
- Tournas VH, Rivera Calo J, Sapp C. Fungal profiles in various milk thistle botanicals from US retail.. Int J Food Microbiol. 2013. PMID 23624536. DOI 10.1016/j.ijfoodmicro.2013.03.026. (abstract)
- Tvrdý V, Pourová J, Jirkovský E et al.. Systematic review of pharmacokinetics and potential pharmacokinetic interactions of flavonolignans from silymarin.. Med Res Rev. 2021. PMID 33587317. DOI 10.1002/med.21791. (abstract)
- Voroneanu L, Nistor I, Dumea R et al.. Silymarin in Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.. J Diabetes Res. 2016. PMID 27340676. DOI 10.1155/2016/5147468. (abstract)
- Wang C, Shang Y, Kanaan G et al.. Silymarin for adults with metabolic dysfunction-associated steatotic liver disease.. Cochrane Database Syst Rev. 2025. PMID 40552569. DOI 10.1002/14651858.CD015524.pub2. (abstract)
- Yin S, Zhu F, Liu Y et al.. Effects of silymarin on insulin resistance and sensitivity: A systematic review and meta-analysis of randomized controlled trials.. Diabetes Res Clin Pract. 2025. PMID 39855603. DOI 10.1016/j.diabres.2025.112008. (abstract)
- de Avelar CR, Pereira EM, de Farias Costa PR et al.. Effect of silymarin on biochemical indicators in patients with liver disease: Systematic review with meta-analysis.. World J Gastroenterol. 2017. PMID 28785154. DOI 10.3748/wjg.v23.i27.5004. (abstract)
- van Erp NP, Baker SD, Zhao M et al.. Effect of milk thistle (Silybum marianum) on the pharmacokinetics of irinotecan.. Clin Cancer Res. 2005. PMID 16278402. DOI 10.1158/1078-0432.CCR-05-1288. (abstract)
Where to buy
Check the label first. Whatever you buy, look for these:
- The herb is the first or only ingredient
- Organic or lab-tested if that matters to you
- Loose leaf or tea bags, and how long they have been stored
- If you take medicines or are pregnant, ask a pharmacist about the herb first
Talk to a pharmacist or doctor before you start any supplement, especially if you take medicines. See the Safety tab for interactions.
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