Milk Thistle (Silybum marianum)

Milk Thistle (Silybum marianum)

Botany, Geographical Distribution, and Horticultural Information of Milk Thistle (Silybum marianum)


Milk thistle (Silybum marianum) is a flowering plant belonging to the Asteraceae family. It is characterized by its distinctive appearance, featuring glossy green leaves with white veins and large purple to pink thistle-like flowers. The plant can grow up to 2 meters in height and has a robust, grooved, and more or less cottony stem. The leaves are oblong to lanceolate and can be up to 50 cm long and 12 cm wide. The flowers, which bloom from June to August, are enclosed in a bristly involucre.

Geographical Distribution:

Originally native to the Mediterranean region, milk thistle has spread to various parts of the world, including most temperate areas. It is commonly found in Southern Europe, Asia, Central Asia, and India, and has naturalized in parts of Europe, North America, South America, Australia, and New Zealand. The plant thrives in dry, rocky soils and is often found in overgrazed pastures, wastelands, and along roadsides.

Horticultural Information:

1. Cultivation: Milk thistle is cultivated as a medicinal plant but can also be a troublesome weed. It prefers sunny locations and well-drained soils. The plant is drought-resistant and can tolerate poor soil conditions.

2. Propagation: Milk thistle is propagated mainly by seeds. Each flower head can produce about 190 to 200 seeds, which are dispersed by wind. The seeds have a high germination rate and can remain viable in the soil for up to 9 years.

3. Uses: Milk thistle is primarily grown for its seeds, which are used in traditional medicine. The seeds contain silymarin, a group of compounds said to have antioxidant and liver-protecting properties. The plant is also used as a food source; the leaves, stems, roots, and flower heads can be consumed.

4. Management: As a weed, milk thistle can be difficult to control due to its long taproot and high seed production. Mechanical control methods and herbicides are commonly used for its management in agricultural settings.


1. “Milk Thistle (Silybum Marianum L.) as a Novel Multipurpose Crop for Agriculture in Marginal Environments: A Review” –
2. “Silybum marianum” –
4. “Cultivation of milk thistle (Silybum marianum L. Gaertn.), a medicinal weed” –
5. “Environment-Driven Changes in the Functional Traits of Milk Thistle Along an Altitudinal Gradient in the Semi-Arid Environment” –
6. “Silybum marianum” –
7. “Silybum marianum Profile” –
8. “Milk Thistle (Silybum marianum L.)” –
9. “Silybum marianum – Plant Finder” –


History, Traditional Herbal & Culinary Uses of Milk Thistle (Silybum marianum)


Milk thistle, scientifically known as Silybum marianum, has been used for over 2000 years for its medicinal properties. The plant is native to Northern Africa, Southern Europe, Southern Russia, and Anatolia. Its use in traditional medicine dates back to the ancient Greeks and Romans, who recognized its value in treating liver and gallbladder diseases. The name ‘milk thistle’ is derived from the milky white fluid that comes out of the plant’s leaves when they are crushed.

Traditional Herbal Uses:

1. Liver and Gallbladder Disorders: Historically, milk thistle has been used to treat liver problems, including cirrhosis, jaundice, hepatitis, and gallbladder disorders. The active compound in milk thistle, silymarin, is believed to have hepatoprotective properties.

2. Digestive Health: Milk thistle has been traditionally used to relieve symptoms associated with overindulgence of food and drink, such as indigestion and upset stomach.

3. Detoxification: The herb has been used for its detoxifying properties, helping to cleanse and rejuvenate the liver.

4. Other Medicinal Uses: Historically, milk thistle was also used as a tonic for the heart, to stimulate the kidneys and veins, and to reduce cholesterol levels.

Culinary Uses:

1. Edible Parts: All parts of the milk thistle plant have been used as food. The young leaves can be eaten raw in salads or cooked like spinach. The flower heads can be prepared similarly to artichokes.

2. Seeds: The seeds are the most commonly used part of the plant for both medicinal and culinary purposes. They can be ground and used as a coffee substitute or added to cereals and salads.

3. Roots: The roots of the milk thistle plant can be consumed raw or cooked. They have a taste similar to a radish.


1. “Milk thistle: early seeds of potential” –
2. “Milk Thistle | British Herbal Medicine Association” –
3. “The food plant Silybum marianum (L.) Gaertn.: Phytochemistry, Ethnopharmacology and clinical evidence” –
4. “Silybum marianum (L.) GAERT. | Milk Thistle | Plant Encyclopaedia” –
5. “Silybum marianum – Wikipedia” –
6. “Silybum marianum – Useful Temperate Plants” –
7. “THISTLE – MILK (Silybum marianum)” –
8. “Milk Thistle – blessed by the Virgin Mary herself!” –


Pharmacological and Medicinal Studies on Milk Thistle (Silybum marianum)


Milk thistle (Silybum marianum) has been extensively studied for its pharmacological properties, particularly for its active component, silymarin. Silymarin is a complex of flavonolignans, primarily consisting of silybin, which is the most active and abundant constituent.

Key Pharmacological Findings:

1. Liver Protection and Hepatoprotective Effects: Silymarin has been recognized for its liver-protecting properties. It is used in the treatment of liver diseases, including alcoholic cirrhosis, hepatitis, and liver damage caused by toxins. Silymarin acts as an antioxidant, stabilizes liver cell membranes, and stimulates liver regeneration.

2. Anticancer Properties: Studies have shown that milk thistle possesses anticancer effects against various types of cancers, including gastric, prostate, skin, breast, and liver cancers. It modifies the induction of apoptosis, inhibits the STAT3 pathway, and impedes the growth of cancer cells.

3. Antioxidant Activity: Silymarin exhibits significant antioxidant properties, protecting against oxidative stress and free radical damage.

4. Anti-Inflammatory Effects: Milk thistle has anti-inflammatory properties, which contribute to its therapeutic effects in liver diseases and other inflammatory conditions.

5. Cardioprotective and Nephroprotective Activities: Silymarin has shown potential in protecting the heart and kidneys, suggesting its use in cardiovascular and renal diseases.

6. Neuroprotective Effects: There is emerging evidence of milk thistle’s neuroprotective properties, indicating potential benefits in neurodegenerative diseases.

7. Antidiabetic Effects: Milk thistle may have beneficial effects in managing diabetes by improving glycemic control.

8. Immunomodulatory Effects: Silymarin has been observed to modulate immune responses, which can be beneficial in autoimmune diseases.

Safety and Tolerability:

Milk thistle is generally well-tolerated, with few reported side effects. Mild gastrointestinal disturbances and nausea are rare. It is considered safe for most individuals when used appropriately.


1. ““Silymarin”, a Promising Pharmacological Agent for Treatment of Diseases” –
2. “Milk thistle (Silybum marianum): A concise overview on its chemistry, pharmacological, and nutraceutical uses in liver diseases” –
3. “Silybum Marianum – an overview” –
4. “Assessment report on Silybum marianum (L.) Gaertn., fructus” –
5. “Health Benefits of Silybum marianum: Phytochemistry, Pharmacology, and Applications” –
6. “New Therapeutic Potentials of Milk Thistle (Silybum marianum)” –
7. “Pharmacological and Pharmacognosticl Activity of Silybum marianum” –
8. “Full article: Silymarin: a review on paving the way towards promising pharmacological agent” –
9. “Milk thistle Information” –


Specific Phytochemicals in Milk Thistle (Silybum marianum)

Milk Thistle, scientifically known as Silybum marianum, is rich in a variety of individual phytochemical molecules. These compounds are primarily responsible for the plant’s medicinal properties. Here is a list of specific phytochemicals identified in Milk Thistle:

1. Silybin (Silibinin): The most active and abundant constituent of silymarin, a complex of flavonolignans found in Milk Thistle. It is divided into two isomers, Silybin A and Silybin B.

2. Isosilybin: Another component of silymarin, existing as Isosilybin A and Isosilybin B.

3. Silydianin: A flavonolignan present in the silymarin complex.

4. Silychristin: Also part of the silymarin complex, contributing to the plant’s hepatoprotective effects.

5. Taxifolin: A flavonoid found in Milk Thistle, known for its antioxidant properties.

6. Apigenin 7-O-β-(2″-O-α-rhamnosyl)galacturonide: A flavonoid glycoside identified in Milk Thistle.

7. Kaempferol 3-O-α-rhamnoside-7-O-β-galacturonide: Another flavonoid glycoside found in the plant.

8. Apigenin 7-O-β-glucuronide: A flavonoid derivative present in Milk Thistle.

9. Apigenin 7-O-β-glucoside: A glycosylated form of apigenin found in the plant.

10. Apigenin 7-O-β-galactoside: Another glycosylated derivative of apigenin in Milk Thistle.

11. Kaempferol-3-O-α-rhamnoside: A flavonoid contributing to the plant’s pharmacological properties.

12. Kaempferol: A flavonoid known for its antioxidant activity.

13. Quercetin: A well-known flavonoid with various health benefits, found in Milk Thistle.

14. Linoleic Acid: A fatty acid present in the plant, particularly in the seeds.

15. Oleic Acid: Another fatty acid found in Milk Thistle, contributing to its nutritional value.


1. “Comparative Assessment of Phytoconstituents, Antioxidant Activity and Chemical Analysis of Different Parts of Milk Thistle Silybum marianum L” –
2. “Silybum Marianum – an overview” –
3. “Phenolic profile and in vitro antioxidant power of different milk thistle cultivars” –


Contraindications and Safety of Milk Thistle (Silybum marianum)


1. Allergic Reactions: Individuals allergic to plants in the Asteraceae family may also be allergic to milk thistle. Allergic reactions can include rash, pruritus, and anaphylaxis.

2. Pregnancy and Breastfeeding: The safety of milk thistle during pregnancy and breastfeeding is not well-established. Pregnant and breastfeeding women should consult a healthcare provider before using milk thistle.

3. Hormone-Sensitive Conditions: Milk thistle might act like estrogen in the body. Women with hormone-sensitive conditions, such as breast cancer, uterine cancer, ovarian cancer, endometriosis, or uterine fibroids, should avoid using milk thistle.

4. Drug Interactions: Milk thistle can interact with certain medications, including drugs metabolized by the liver’s cytochrome P450 enzyme system, such as statins, birth control pills, and some cancer medications.


1. General Use: Milk thistle extract is generally considered safe for most people when taken by mouth. It is well-tolerated, with few reported side effects.

2. Gastrointestinal Issues: Some people may experience gastrointestinal issues, such as diarrhea, constipation, nausea, vomiting, and abdominal bloating.

3. Dosage: Milk thistle is considered safe in dosages of 420 mg/day orally in divided doses for up to 41 months. For liver disease treatment, the dosage can be increased as per medical advice.

4. Rare Side Effects: Although rare, some individuals may experience headaches, joint pain, or sexual dysfunction.


1. “MILK THISTLE: Overview, Uses, Side Effects, Precautions, Interactions, Dosing and Reviews” –
2. “Milk thistle Information” –
3. “Milk thistle – Mayo Clinic” –
4. “Safety and toxicity of silymarin, the major constituent of milk thistle extract: An updated review” –
5. “Milk Thistle Uses, Benefits & Dosage” –
6. “Milk Thistle: Benefits and Side Effects” –
7. “Milk Thistle – StatPearls” –
8. “Milk thistle: benefits and contraindications – a complete guide” –
9. “Milk thistle | Complementary and Alternative therapies” –
10. “Milk Thistle: Drug Interactions & Contraindications” –