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Milk thistle
Milk thistle — what the European monograph actually supports, what it is not for, the form and how long it is meant to be used, side effects, and the 2 medicine interactions documented for it.
This is a reference page, not a diagnosis and not a prescription. Herbal products are real pharmacology: they have effects, side effects and interactions with medicines. Tell your doctor and your pharmacist everything you take, including teas and supplements, and never stop or change a prescribed medicine because of anything you read here.
What it is
Silybum marianum (L.) Gaertn. — fruit (Silybi mariani fructus); the active fraction is silymarin
Local names across the region this site serves: maarjaohakas (ET) · maarianohdake (FI) · расторопша (RU).
Grouped here under Digestion, bloating and the bowel. Regulatory position: EU herbal monograph — traditional use.
What the evidence supports
The registered indication: Relief of digestive complaints, including a feeling of fullness and indigestion.
Milk thistle's reputation as the liver herb rests on two very different things that marketing blends into one. Intravenous silibinin, a purified constituent, is a genuine hospital treatment for death-cap mushroom (Amanita phalloides) poisoning and is stocked by European poison centres — a controlled medicine given by drip in intensive care. Oral silymarin capsules are a supplement, and systematic reviews of their use in alcohol-related and viral liver disease have repeatedly concluded that the evidence is inconclusive; NCCIH's summary says the same. The EU monograph indication is digestive, not hepatic. It is a well-tolerated plant with an unusually large gap between what it is licensed for and what it is bought for.
C — Traditional use only Plausible from thirty or more years of use, which is what a traditional-use registration means. No clinical evidence was required and none has settled it.
What it is not for
Hepatitis, fatty liver disease, cirrhosis, or "detox" after a heavy weekend. Raised liver enzymes are a reason for a work-up, not a capsule.
Form, strength and how long
Standardised silymarin extracts in capsules and tablets; the crushed fruit as a tea extracts very little silymarin, which is poorly water-soluble.
Duration. Short courses for the registered digestive indication.
No gram figure appears on this page on purpose. The plant part, the extraction solvent and the drug-to-extract ratio together define a preparation, and a number taken from one does not describe another. The reasoning is set out on the hub; the amount that applies to you is the one printed on the pack you are holding, and a pharmacist will read it with you.
Side effects
Generally well tolerated. A mild laxative effect, bloating and nausea are the usual reports. Allergic reactions occur in people sensitive to the daisy family (Asteraceae).
Who should avoid it
Not established in pregnancy or breastfeeding. Anyone with a diagnosed liver condition should be taking it, if at all, with the knowledge of the team managing that condition.
Interactions with medicines
| Medicine or substance | What is described |
|---|---|
| Prescription medicines generally | Silymarin's effect on the enzymes that clear medicines has been studied and is generally small. The practical issue is different: people take milk thistle precisely when they are already on something — often for a liver problem — so it belongs in the conversation with the doctor managing that, not in a private decision. |
| Diabetes medicines and insulin | Some trials in type 2 diabetes report modest reductions in blood glucose with silymarin. If you are on glucose-lowering medicines, that is a reason to monitor rather than to assume nothing changed. |
The reverse view — start from the medicine rather than the plant — is in the medicine, food and alcohol interactions reference, and summarised for every herb on this site.
Sources: European Medicines Agency — Committee on Herbal Medicinal Products (HMPC), European Union herbal monographs · NIH National Center for Complementary and Integrative Health — herb fact sheets · checked 2026-09-06
Frequently asked questions
What is milk thistle used for?
Relief of digestive complaints, including a feeling of fullness and indigestion. Milk thistle's reputation as the liver herb rests on two very different things that marketing blends into one. Intravenous silibinin, a purified constituent, is a genuine hospital treatment for death-cap mushroom (Amanita phalloides) poisoning and is stocked by European poison centres — a controlled medicine given by drip in intensive care. Oral silymarin capsules are a supplement, and systematic reviews of their use in alcohol-related and viral liver disease have repeatedly concluded that the evidence is inconclusive; NCCIH's summary says the same. The EU monograph indication is digestive, not hepatic. It is a well-tolerated plant with an unusually large gap between what it is licensed for and what it is bought for.
Does milk thistle work?
Graded C here: Plausible from thirty or more years of use, which is what a traditional-use registration means. No clinical evidence was required and none has settled it. Hepatitis, fatty liver disease, cirrhosis, or "detox" after a heavy weekend. Raised liver enzymes are a reason for a work-up, not a capsule.
How much milk thistle should I take?
This reference does not print gram figures, because they do not transfer between preparations of different extract strength. What can be said honestly is the form and the duration: Standardised silymarin extracts in capsules and tablets; the crushed fruit as a tea extracts very little silymarin, which is poorly water-soluble. Short courses for the registered digestive indication.
What are the side effects of milk thistle?
Generally well tolerated. A mild laxative effect, bloating and nausea are the usual reports. Allergic reactions occur in people sensitive to the daisy family (Asteraceae).
Does milk thistle interact with medicines?
Yes — documented for Prescriptions, Diabetes medicines. Each one is described on this page, with a link to the medicine-side reference where one exists.
Others in digestion, bloating and the bowel
Peppermint
Symptomatic relief of minor spasms of the gastrointestinal tract, flatulence and abdominal pain, especially in irritable bowel syndrome, for gastro-resistant oil capsules; the leaf is registered for mild digestive complaints.
Caraway
Mild spasmodic gastrointestinal complaints including bloating and flatulence.
Ginger
Prevention of nausea and vomiting in motion sickness, and mild digestive complaints such as bloating.
Fennel
Mild spasmodic gastrointestinal complaints including bloating and flatulence; and as an expectorant in cough associated with a cold.
Turmeric
Relief of digestive disturbances such as a feeling of fullness and flatulence.
Liquorice
Digestive complaints including burning sensation and dyspepsia; and as an expectorant in cough associated with a cold.
Keep the whole list in one place
TempoLife logs supplements alongside food, sleep and how you actually felt — so the answer to "what are you taking?" is a screen, not a guess.