Milk Thistle

Milk Thistle
© Sertürner Bildarchiv

Botanical name

Milk Thistle - Silybum marianum (L.) Gaertn. (syn. Carduus marianus L.)


Daisy family (Asteraceae)

Common name

Silver milk thistle, Elephant thistle, Blessed milk thistle

Useful information about the plant

The milk thistle is native in southern Europe, the Caucasus, and Asia Minor, and to North Africa and the Canary Islands, and has been introduced in many countries. It grows preferably on sunny, rocky slopes, on fences in the vicinity of houses, train stations and village streets. Milk thistle for medicinal purposes only comes from crops. The genus name Silybum comes from the Greek "silibon" (etymologically Syllibon) = tassel.
The thistle-like plant grows for a year or two. It grows 60 to 150cm high and blossoms from June to September with purple daisy heads, which consist only of tubular flowers. Their thistle-like appearance is due to the outer husks of the blossom, ending in strong, sharp thorny spikes. The individual lobes of the stalks including the leaves also end in pointy yellow spines. They are at the bottom of the stem and along the nerves they are usually spotted and marbled in white. The brown-spotted fruit has a shiny white pappus as a vessel of flight.

Medicinally used plant parts (drug)

The ripe fruit freed by the pappus is used. The commercially available drug is derived exclusively from crops, partly in northern Germany, but it is mostly imported, mainly from Argentina and China, Romania and Hungary.

Ingredients of the drug

Milk thistle fruits contain Flavolignane (silymarin) and fatty oil.

Descriptions of the quality

The quality of the following drugs or drug preparations is specified in the European Pharmacopoeia (Ph. Eur.):

  • Milk thistle fruits (fructus Silybi Marian)
  • Preset (standardised) purified milk thistle dried extract (Silybi mariani extractum siccum raffinatum et normatum)

Medical Application

Recognised medical use

Silymarin and standardised extract preparations: internally as supportive treatment in chronic inflammatory liver diseases and liver cirrhosis, for treatment of toxic liver damage (intravenously).

Traditional use

Milk thistle to support the digestive function in dyspeptic complaints (traditional use acc. to § 109a).

Medicinal herbal preparations in finished drug products

  • Silymarin in standardised dried extracts (DEV from 25-40:1 to 60-70:1 - Extraction solvent: acetone, ethyl acetate or ethanol 96% V / V)
  • Milk thistle tincture in liquid preparations


Prepared drugs: see package insert;
Teas are not recommended because they will not produce the effective dose.


Milk thistle preparations must be avoided in any form by people who have existing allergies to milk thistle. There is as yet no experience on safety of its use during pregnancy, breast-feeding or in children under 12 years old so do not use without consulting a doctor.

Side effects

Rarely mild laxative effect and hypersensitive reactions


None known


Drug monographs

Commission E, ESCOP, WHO (Vol. 2)

Further reading

Wichtl: Teedrogen und Phytopharmaka, pg. 627
Schilcher: Leitfaden Phytotherapie, pg. 174
Van Wyk: Handbuch der Arzneipflanzen, pg. 300
Kommentar zum Europäischen Arzneibuch (Milk thistle fruit, no. 1860; Milk thistle dried extract, no. 2071)

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