[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Herbal products and dietary supplements](https://durgical.com/en/pharmacology/classes/herbal-products-and-dietary-supplements/) › Milk thistle

# Milk thistle

## Herbal products and dietary supplements?

Herbal products and dietary supplements

A herbal supplement (silymarin) widely sold for the liver. Good trials have not shown that it helps liver disease.

Updated Nov 12, 2026

Also called: Silybum marianum, silymarin

## Quick facts

**Group**
[Herbal products and dietary supplements](https://durgical.com/en/pharmacology/classes/herbal-products-and-dietary-supplements/)

**Target**
No established target (silymarin extract)

**Used for**
No proven indication · Studied for blood sugar control

**Key effects**
Bloating · Allergic reactions

**Monitor**
Ask every patient about supplements

**ATC**
A05BA03

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

Milk thistle extract comes from the seeds of Silybum marianum. Its main component is silymarin, a mixture of compounds that is promoted as protecting liver cells. Studies in alcohol-related liver disease, hepatitis B and C and fatty liver disease have given conflicting or inconclusive results, and two NIH-funded trials in hepatitis C and fatty liver found no benefit. Product content can also differ from the label.

- Seed extract rich in silymarin
- Promoted to protect liver cells
- Good trials have not shown benefit

## Indications

- No proven indication; studied without clear benefit in chronic liver disease, including fatty liver disease and hepatitis C [Metabolic dysfunction-associated steatotic liver disease (MASLD/NAFLD) →](https://durgical.com/en/conditions/metabolic-dysfunction-associated-steatotic-liver-disease/)
- Studied for blood sugar control in type 2 diabetes; evidence is limited

## Adverse effects

- Bloating, nausea and gas
- Allergic reactions, especially in people allergic to ragweed, chrysanthemum, marigold or daisy

## Contraindications

- Allergy to plants of the daisy family (Asteraceae)
- Not a substitute for proven treatment of liver disease

## Key interactions

**Deferiprone**
Silymarin inhibits UGT1A6, the enzyme that inactivates deferiprone; the combination is avoided

## What is monitored

- Ask every patient about supplements, including liver products
- Liver tests are guided by the underlying disease, not by the supplement

## Administration and safety

- Sold as a supplement; content and purity can differ from the label, and contamination has been found
- Its use is recorded in the medication history

## Pregnancy and breastfeeding

Little is known about its safety in pregnancy or breastfeeding.

## Nursing care

- Ask specifically about herbal liver products, which patients often do not mention
- Explain that it has not been shown to treat liver disease
- Ask about allergy to daisy-family plants

## Pharmacokinetics

**Absorption**
Taken by mouth as capsules, tablets or extracts; content varies between products

## Memory aid

MILK the thistle and you get siLYmarin, but the trials did not deLIVER.

## Test yourself

Think of the answer, then tap the question to see it.

## What is the main component of milk thistle extract?

Silymarin, a mixture of compounds from the seeds of Silybum marianum.

## Has milk thistle been shown to treat liver disease?

No. Results are conflicting or inconclusive, and two NIH-funded trials in hepatitis C and fatty liver found no benefit.

## Which iron chelator should not be combined with silymarin, and why?

Deferiprone, because silymarin inhibits UGT1A6, the enzyme that inactivates it.

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[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## Connections

## Related drugs 3

- [Deferiprone](https://durgical.com/en/pharmacology/deferiprone/)
- [St John's wort](https://durgical.com/en/pharmacology/st-john-s-wort/)
- [Ginkgo](https://durgical.com/en/pharmacology/ginkgo/)

## Related conditions 1

- [Metabolic dysfunction-associated steatotic liver disease (MASLD/NAFLD)](https://durgical.com/en/conditions/metabolic-dysfunction-associated-steatotic-liver-disease/)

[← Back to the class: Herbal products and dietary supplements](https://durgical.com/en/pharmacology/classes/herbal-products-and-dietary-supplements/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [Milk Thistle: Usefulness and Safety](https://www.nccih.nih.gov/health/milk-thistle) (National Center for Complementary and Integrative Health (NCCIH), 2025); [DailyMed - DEFERIPRONE tablet, coated](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=67139215-1154-4e1a-ae15-0f3cd8af5177) (DailyMed (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=A05BA03) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/milk-thistle/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/milk-thistle/