Milk Thistle

Silybum marianum · Silymarin

Snapshot

Indications	Contraindications
Nonalcoholic fatty liver disease¹ Antituberculosis liver injury² Chemotherapy-related hepatotoxicity³ Type 2 diabetes glycemic control^4–8 Dyslipidemia^{4, 5, 7} Hand-foot syndrome prevention⁹	Daisy or ragweed family allergy¹⁰

Milk thistle (Silybum marianum) fruit extract, silymarin, is a mixture of flavonolignans with antioxidant and anti-inflammatory actions shown mainly in preclinical studies. Its benefit for liver disease in people is not yet established¹¹. Supplementation follows from that hepatoprotective effect: it is used for fatty liver disease, for liver injury from medications such as antituberculosis therapy and chemotherapy, and for glycemic and lipid support in type 2 diabetes.

Glycemic effects appear in type 2 diabetes, though a 2025 meta-analysis found limited support for insulin resistance outcomes⁶. In a 2026 network meta-analysis of randomized trials, topical silymarin reduced severe chemotherapy-induced hand-foot syndrome, but a larger trial is still needed to confirm it⁹. Products are mostly capsules of seed extract or powder; poor oral bioavailability has driven newer formulations, covered in Form comparison¹².

Allergy to related plants in the daisy and ragweed family is the main reason to withhold¹⁰. Per MSKCC, patients on sirolimus, haloperidol, or risperidone are told to talk with their healthcare provider before use¹⁰.

Last updated October 16, 2026. Read how we make monographs.

In the full monograph

84 sources, 70 studies

When to useThe situations practitioners use it for, each with the reason and the study behind it.
SafetyWho should avoid it, who needs extra care, and the side effects reported in studies.
InteractionsThe medicines and supplements it interacts with, the effect of each, and what labeling says to watch.
Protocol notesThe doses used in studies, how and when they were taken, and how the forms on the market compare.
How it worksWhat it is and how it works in the body, in plain terms.
Published studiesThe studies behind each use, popular claims checked against them, and trials still under way.
Word of mouthWhat patients and practitioners report online, kept separate from the clinical evidence.
Clinical perspectiveA closing read of where the evidence is solid, where it is thin, and what has not been studied.

Snapshot

In the full monograph

Sources