Milk Thistle

Carduus marianus syn. Silybum marianum

Herbs gallery - Milk Thistle

Common names

  • Mary's Thistle
  • Milk Thistle
  • Silybum
  • Silymarin
Milk thistle is known by many names, including St. Mary's, Marian, and Our Lady's thistle. According to botany, milk thistle is known as Silybum marianum, and belongs to the Asteraceae family. There is liberal mention of milk thistle in many ancient as well as some modern European literature where it is referred to as Carduus marianus. Over the ages, many other plants were also called milk thistles, but now the authorities have set this name aside only for this particular species of herbs. Indigenously found in the Mediterranean region of Europe, milk thistle is a tall herb with spiky leaves and contains a milk-like liquid. Currently, milk thistle also grows naturally in California as well as other eastern regions of the United States. Many people often confuse milk thistle with blessed or holy thistle simply because of the similarity of their religiously motivated similar names. Basically, blessed or holy thistle is a different plant scientifically known as Cnicus benedictus. Confusion also exists relating to the part of the milk thistle that is used for medicinal purpose. In fact, the part of milk thistle that is used is the small firm fruits theoretically called achenes. Achenes are used after removing a fluffy thicket or pappus from them. The confusion over achenes continues when many of the herbal literature in English wrongly refer to them as seeds. Though the achenes appear to look like seeds, they are actually fruits with hard coatings. What is worse is the fact that in recent times a number of herbal medicine manufacturers have entered the markets with products containing milk thistle leaves. This is not only confusing, but misleading too as the milk thistle leaves do not possess any kind of healing benefit. While no therapeutic properties have yet been found in the milk thistle leaves, all scientific researches involving the herb has been carried out on its fruits, especially a particular extract from the milk thistle fruits. In fact, over the ages, milk thistle fruits have been used to heal numerous ailments and disorders, especially complaints regarding the liver. Except for the simple use as an astringent, the medicinal application of milk thistle fruit extract has been virtually abandoned since the early twentieth century. Instead, in 1947, the United States Dispensatory published one small section regarding the medicinal and especially milk thistle fruit extract's chronological facets. Thirty years after this, a group of German scientists initiated a chemical research of the milk thistle fruit and were successful in segregating a coarse combination of anti-hepatotoxic values selected silymarin. Milk thistle fruits were found to contain 1 to 4% of silymarin. Further researched discovered that silymarin comprised large quantity of flavonolignans. The flavonolignans included mainly silybin along with isosilybin, dehydrosilybin, silydianin, sily-christin and many more of the kind. Laboratory examinations on small animals have proved that silymarin provides a defense mechanism that protects the liver from different kinds of poisons like the phallotoxins of the lethal amanita and is believed to be the only antidote when suffering from amanita poisoning. Not only experiments on animals, but even the milk thistle fruit extract or silymarin tests on humans have also proved to be positive. It has been found to be beneficial for curing hepatitis as well as cirrhosis from several causes. Scientific researches have shown that silymarin has sufficient healing properties and is capable of safe guarding the whole liver cell or the liver cells that have not been ruined irrevocably as they effectively act on the cell coverings by preventing toxic materials from entering the cells. Silymarin also helps in the synthesis of proteins and in doing so it speeds up the cell renewal procedure as well as re-birth of liver cells. These findings have eventually led the health authorities in Germany to permit the use of milk thistle as a supplementary remedy for swollen livers and different types of cirrhosis. Since silymarin does not dissolve in water, milk thistle does not prove to be much useful when it is used like a tea as its activity is diminished. Researches have established that any beverage made from milk thistle contains less than 10% of the medicinal properties that is found in the original plant. Compared to other herb extracts, silymarin is less absorbed by the gastro-intestinal tract. On an average only 20% to 50% of the substance is soaked in by the system. Hence, owing to its insoluble nature as well as its poor absorbability by the gastro-intestinal zone, silymarin is best effective when it is dispensed parenterally (the form of injections). If one desires to intake milk thistle orally, it needs to be in a concentrated form. Therefore, it is natural that in some countries milk thistle is sold in the form of 200 mg capsule supplementary diet. It may be noted here that a 200 mg milk thistle condensed extract contains 140 mg silymarin. Normally, milk thistle does not have any adverse side effect and so far there has been no case of toxic effect owing to the use of the herb extract. However, researches conducted on about 2169 people showed that only 1% or as many as 21 persons complained of temporary gastro-intestinal side effects following the use of milk thistle. This, in fact, makes milk thistle extract an effective and tolerable remedy. As mentioned earlier, milk thistle is native to the Mediterranean region of Europe and was carried to the United States, where it has adapted well with the soil and climatic conditions. Today it grows naturally in the wild in California as well as in the East Coast areas. Milk thistle contains a white milky juice which perhaps gives it one of its names. The leaves of the plant are prickly with white stains along the spine which many believe to be an effect of Virgin Mary's milk. Hence, the plant is also known as Our Lady's thistle. Long ago, the herb is reported to have been used to boost milk production, but this is most likely owing to the herb's name and involvement. It is interesting to note that people were aware about the therapeutic benefits of milk thistle even two thousand years ago. Long ago, Pliny the Elder praised the herb for its usefulness in removing toxics from the human system. Even herbal practitioners of the Medieval Ages applied this medicinal benefit of the plant and the herbalists in England accepted this value of the plant. However, the herb was not too popular among the physicians thereafter and during the early twentieth century its therapeutic values were only known to the homeopaths. It was only in the 1950s that there was a renewed interest in the medicinal values of the plant and the scientists undertook fresh researches to ascertain the usefulness of milk thistle. During these researches, it was found that the fruit of milk thistle, especially a particular extract from it possessed medicinal use. Henceforth, the small firm fruit of milk thistle began to be used widely after removing its fluffy part called 'pappus'.

Parts used

Seeds, flower heads.


In earlier times, people consumed milk thistle flower heads after boiling them much in the way they ate artichokes. It was basically used as a spring tonic as there was a scarcity of green vegetables soon after the harsh winter months. While many women consumed milk thistle to augment milk secretion in the mammary, many others used the herb to heal melancholia or depressions arising out of liver disorders. In his Herball published in 1597 Gerard praised milk thistle saying that he considered the herb to be the best remedy to cure depressions. Currently, milk thistle is no longer consumed as a spring tonic, but used as a herbal remedy by the Western physicians to safeguard the liver as well as its metabolism. Milk thistle derivatives are also useful for regenerating the liver cells. Many herbal physicians use milk thistle to cure hepatitis as well as jaundice. It is a very useful remedy for the liver when it is under trauma owing to infection, excessive alcoholism or owing to chemotherapy while treating cancer. When milk thistle is used by cancer patients undergoing chemotherapy, it is beneficial in restricting the damages done to the liver owing to radiation therapy as well as helps in facilitating recuperation from the side effects after the chemotherapy treatment is over.

Habitat and cultivation

Originally from the Mediterranean region in Europe, today milk thistle grows and thrives in natural conditions all over Europe as well as in California and Australia. Milk thistle grows best and flourishes in uncluttered regions. It requires a sunlit position and self-seeds fast. Currently, milk thistle is commercially grown as a decorative plant. The flower heads are harvested when they are in full blossom during the early summer season, while the plant's seeds are collected in late summer.


After people had lost interest and awareness in milk thistle and its benefits in the early twentieth century, German researchers began fresh studies on the plant in 1970s. Their research concentrated on silymarin that is found in milk thistle seeds. Silymarin extracts from milk thistle has a protective action on the liver and is hence widely used as a remedy for various kinds of liver disorders. Silymarin not only helps the liver to function properly, but also safeguards it from damages and toxins. Researches have established that the lethal effects of consuming carbon tetrachloride or death cap mushrooms can be prevented if silymarin is taken immediately before their intake. Silymarin is also capable of curing the ailments arising out of this if taken within 48 hours of consuming carbon tetrachloride or death cap mushrooms. Herbal physicians in Germany have effectively used silymarin even to cure hepatitis and cirrhosis of the liver.


The principal extract of milk thistle, silymarin (4% to 6% in ripe fruit), is composed of several polyphenolic tlavonolignans. The major component (60%) is silybin (also known as silibinin or silybinin), and it is also the most biologically active; other components include silichristin (also known as silychristin, silycristine or silicristin), a metabolic stimulant, and silydianin. Silymarin is found in highest concentrations in the fruit of the plant. Other constituents are flavonoids, a fixed oil (16% to 18%), betaine, trimethylglycine (TMG) and amines.

Usual dosage

There are different dosages of silymarin for healing different ailments. Many people suffering from liver disorders and/ or damaged liver conditions consume 420 mg of silymarin extracted from milk thistle every day. The herbal extract contains 70% - 80% silymarin. Researches as well as medical practice show that when the herbal extract is taken in this manner it normally produces results within eight to twelve weeks. When there is a positive result, the dosage of the herbal medicine can be lowered to 280 mg of silymarin daily. In fact people may also take this lower dosage of silymarin as a preventive measure from the liver disorders. If someone likes it, he or she may ground 12 - 15 grams of milk thistle seeds and consume the powder directly or prepare a tea with it. However, this should not be taken in as a remedy for the liver conditions.

Side effects and cautions

Fortunately, intake of milk thistle or its extract is not known to have any adverse side effects and hence it can be used by everyone, including pregnant and lactating women. However, in some people silymarin may lead to laxative effect as it does not incite the functions of the liver or gall bladder. Even if such side effects occur, they are temporary in nature and end within a couple of days.