Thistle, Milk

Milk Thistle

Silybum marianum

Botanical Family: Asteraceae (Daisy family)

Botanical Description

Silybum marianum is a striking biennial or annual growing 60-150cm tall. The large, glossy leaves are deeply lobed with spiny margins and distinctive white marbling along the veins – legend says these white streaks came from drops of the Virgin Mary’s milk. Large, purple-pink thistle flowers appear in summer, followed by shiny black seeds (achenes) that contain the medicinal compounds.

Medicinal Actions

Primary actions: Hepatoprotective, hepatorestorative, antioxidant, galactagogue, digestive bitter.

Traditional uses: Used for over 2,000 years as a liver remedy. Dioscorides recommended it for snake bites. European herbalists used it for liver and gallbladder conditions.

Modern research: Extensive scientific study of silymarin (the active compound complex). Shown to protect liver cells from toxins, support regeneration of damaged liver tissue, and act as a powerful antioxidant. Used in hospital settings for Amanita mushroom poisoning.

Body Systems Affected

Hepatic: Primary affinity – protects and regenerates liver cells, supports detoxification pathways.

Digestive: Bitter properties support digestion; traditionally used for gallbladder issues.

Reproductive: Traditional galactagogue (promotes milk flow in nursing mothers).

Safety Information

Excellent safety profile. One of the safest herbal medicines known.

Side effects: Occasionally mild laxative effect or gastrointestinal upset.

Allergies: Those allergic to plants in the Asteraceae family should use with caution.

Pregnancy/Nursing: Generally considered safe; traditionally used to support milk production.

Drug interactions: May affect metabolism of certain drugs through liver enzyme effects. Consult a practitioner if on medications.

Growing Guide

Hardiness: Zones 5-9. Can be grown as annual in colder zones.

Light: Full sun.

Soil: Well-drained, average soil. Tolerates poor, dry conditions.

Sowing: Direct sow in spring after last frost, or start indoors 4-6 weeks earlier. Seeds germinate easily.

Spacing: 90-120cm apart. Plants become large.

Harvesting

Part used: Seeds (achenes).

When to harvest: When the flower heads dry and develop white fluffy pappus, but before seeds disperse.

Method: Cut heads, dry further, then thresh to separate seeds. Wear gloves – the plant is spiny!

Drying & Storage

Seeds should be fully dry before storage. They can be ground as needed or stored whole. Keep in airtight containers in a cool, dark place. Seeds maintain potency for 2-3 years. Note: Silymarin is poorly water-soluble; alcohol extraction or specialized preparations are more effective than simple tea.