Silybum marianum

Milk Thistle

Milk thistle is a potent hepatoprotective herb rich in silymarin, known for supporting liver regeneration, reducing toxicity from drugs and environmental chemicals, improving bile flow, and protecting liver cells from oxidative damage. It is also a gentle galactagogue and aids in treating gallbladder stagnation.

Herbal Actions
Definition and Etymology

Silybum refers to an edible thistle of similar appearance; marianum references the Virgin Mary. The plant’s white-mottled leaves are tied to a legend that the markings came from her milk, giving rise to the name “milk thistle.”

Indications

Milk thistle protects and regenerates liver tissue in cases of toxic mushroom ingestion (always seek emergency care), drug-induced or infectious hepatitis, fatty liver infiltration, cirrhosis, and liver damage due to pharmaceuticals, over-the-counter medications, psychotropics, recreational drugs, solvents, heavy metals, glue, or paint exposure. It improves metabolic liver function, stimulates protein synthesis, increases hepatocyte regeneration, and enhances glutathione production in the liver, intestines, and stomach.

Its antifibrotic actions help prevent collagen infiltration in chronic liver disease, including in diabetic patients with cirrhosis. It accelerates the elimination of heavy metals by increasing metal-binding proteins. Milk thistle increases the solubility of bile, addressing stagnant or inflamed gallbladder conditions such as cholestasis, cholangitis, and pericholangitis.

It may benefit conditions like psoriasis, varicose veins, hemorrhoids, pelvic congestion, and certain menstrual difficulties. The seeds also provide nutritive support and gentle liver cleansing when consumed as food.

Body Systems
History

Milk thistle has been used medicinally since the 1st century CE. Pliny the Elder recommended it for liver-related complaints, and Dioscorides used it as a remedy for snakebites. It became widely used in European folk medicine to stimulate milk production and was later revered in the Middle Ages as a preeminent liver protectant. By the late 1600s, Gerard recommended it for “melancholy disease,” referring to liver and gallbladder disorders.

Identification

A tap-rooted biennial or winter annual in the Carduoideae subfamily, typically 20–30 cm tall in its first-year rosette stage. Leaves are alternate, glossy or slightly tomentose, pinnately lobed with dentate margins, each lobe tipped with a sharp spine. The distinctive variegation forms white mottling on the dark green leaves.

As the plant bolts, smaller leaves clasp the stem. Large discoid flower heads form terminally on long bracted peduncles, enclosed by sharply spined involucral bracts. Flowers are pink to purple with tubular corollas. Fruits are ovoid achenes (6–8 mm) mottled brown and black.

Cautions and Contraindications

Generally considered safe. Ensure adequate dietary fiber intake to help remove toxins excreted via bile. May cause mild laxative effects due to bile stimulation.

Preparations and Dosages

Seeds:

  • Ground and consumed daily as a nutritive liver tonic

Tincture:

  • Dry seeds 1:3 at 70% alcohol
  • Dose: 15–90 drops up to 3×/day

Capsules:

  • 200–400 mg standardized extract (70–80% silymarin) divided into 3 doses

Tea:

  • 8–12 oz/day (limited water solubility)

Culinary:

  • Young leaves and stalks eaten raw; ground seeds added to food

References and Sources

Christina Sinadinos, David Hoffman, Bryan Bowen, all relevant CHSHS lectures.