Milk thistle (Silybum marianum) is often considered a common weed in North America, but has a long medicinal history.
It belongs to the family of plants that include dandelions, Calendula, Zinnia, sunflower, ragweed, and goldenrod subfamilies.
The milk thistle plant has been used for centuries in the treatment of numerous health conditions, mainly those that surround liver function and health.
In historical European literature, the white markings common to the milk thistle weed were believed to have been caused by the Virgin Mary’s milk. The plant grows prolifically throughout European countries, but is now also prevalent throughout the west coast of the United States, particularly California, as well as Australia.



- Supports liver health & detox
- Anti-oxidant & anti-inflammatory properties
- Improves insulin sensitivity & cholesterol
Milk Thistle Plant Overview
Related Topics
- Milk Thistle
- Silybum Marianum
- Silymarin
- Benefits & Uses
- User Reviews
- Use for Diabetes
- Use for Hangovers
- Use for Psoriasis
- Use for Liver Health
- Use for Weight Loss
- Milk Thistle Tea
- Milk Thistle Extract
- Dosage Guide
- How to Take
- Reported Side Effects
- Safe Usage
- Best Supplements
- Combo with Dandelion Extract
- Milk Thistle Tincture
Milk thistle seeds are dried for numerous uses in herbal medicine. The plant itself reaches approximately five feet tall and produces noticeable purple-colored flowering heads that can be consumed much like an artichoke.
Throughout the Middle Ages and in traditional Chinese medicine, the liver was believed to be one of the most important organs in the body, responsible for emotions.
In ancient times, a person who was emotionally erratic or depressed was often treated with the milk thistle because it was believed to repair liver dysfunction.
Silymarin is an extract of the milk thistle seed and is considered the most therapeutically active component of the plant. Although silymarin is most concentrated in the seeds and fruit, it can be found throughout the plant.
The terms silymarin and milk thistle are often used interchangeably to describe the therapeutically active portion of the plan.
How does milk thistle seed work in the body?
The active component found in milk thistle seed is silymarin; a collection of flavonoids, which are known antioxidants. Antioxidants are a first-line defense against oxidation and other damage caused by free radicals. The constituents in milk thistle extract are also believed to restrict the ability of toxins to bind together inside the liver.
Silymarin is a flavonoid complex that includes the flavonolignans silydianin, silychristin, silybin and sylibin. Sylibin constitutes the majority of silymarin and is thought to be the most therapeutically active component of the flavonoid complex. [2]
Flavonolignans are compounds thought to provide anti-inflammatory, antioxidant, and immunomodulatory actions in the body. They’re also known for their anti-viral, anti-proliferative and anti-fibrotic benefits.
These components seek out and destroy damaging free radicals. This has a positive effect on cholesterol and blood vessels. They do this by providing anti-atherosclerotic abilities which can help prevent hardening of the arteries caused by high cholesterol levels.
Considerations for Use
Milk thistle seed extracts and other components of milk thistle are often provided today in the form of silymarin gel caps. The main active ingredient in silymarin is a chemical composition known as silybin, which also contains phosphatidylcholine, one of the ingredients in soy lecithin.
Soy lecithin aids digestive tract absorption of silymarin, enabling nearly one-hundred percent of silymarin to be immediately absorbed by tissues where it’s most needed. Although milk thistle seeds and teas or tinctures made of milk thistle components are less effective than the gel caps, efficacy has been noted in most forms of milk thistle seed supplements as well as silymarin supplements.
Effects of Milk Thistle Seed
The milk thistle seed contains a number of components that promote liver function and support. Dating back to the ancient Greeks and Romans, the herb was often utilized as a liver cleanse.
In the Middle Ages, it was given to individuals who accidentally ate toxic mushrooms to reduce their toxic effect.
The milk thistle plant extract also contains estrogenic compounds that may support memory and boost estrogen. Studies and clinical trials regarding the seed’s efficacy in the treatment of cancers, insulin-resistant diabetes and liver conditions (including hepatitis, cirrhosis, or damage to the liver caused by alcoholism and drug abuse) are still under way, and usually focus on a concentrated source of silymarin.
Safety and Contraindications
When taken as directed, milk thistle plant and seed supplements are generally well tolerated. However, some interactions may occur with other supplements or medications.
Women taking birth control pills should not take many types of herbs as some, including milk thistle, can interfere with the pill’s efficacy. In addition, some people experience a laxative effect because the herb stimulates functions of the liver and the gallbladder. Such side effects are usually temporary.
However, milk thistle seed or other forms of the plant should not be used in conjunction with another plant extract known as yohimbe bark, nor should it be used by people taking phenothiazines, metronidazole, or butyrophenones.
Some people are sensitive to herbal remedies including milk thistle and its components. Common complaints include abdominal cramps, mild diarrhea, nausea, and vomiting. When considering milk thistle seed extracts or products, consult with a physician for proper usage and dosage based on current health, age, and any contributing medical factors.
- Becker-Schiebe, M., Mengs, U., Schaefer, M., Bulitta, M., and Hoffmann, W. Topical use of a silymarin-based preparation to prevent radiodermatitis : results of a prospective study in breast cancer patients. Strahlenther.Onkol. 2011;187(8):485-491.
- Flora K, Hahn M, Rosen H, Benner K. Milk thistle (Silybum marianum) for the therapy of liver disease. Am J Gastroenterol. 1998
- Huseini, H.F., et al. The Efficacy of Silybum Marianum (L.) Gaertn. (Silymarin) in the Treatment of Type II Diabetes: A Randomized, Double-Blind, Placebo-Controlled, Clinical Trial. Phytother Res. 2006 Dec; 20(12):1036-9.
- Melzer J, Rosch W, Reichling J, et al. Meta-analysis: phytotherapy of functional dyspepsia with the herbal drug preparation STW 5 (Iberogast). Aliment Pharmacol Ther 2004;20:1279-87
- Rotem C, Kaplan B. Phyto-Female Complex for the relief of hot flushes, night sweats and quality of sleep: randomized, controlled, double-blind pilot study. Gynecol Endocrinol 2007;23:117-22
- Saller, R., Meier, R., Brignoli, R. The Use of Silymarin in the Treatment of Liver Diseases. Drugs. 2001;61(14):2035-63..
Article last updated on: May 10th, 2018 by Nootriment