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The milk thistle, a liver protector. Used in poisonings caused by hepatotoxic mushrooms

The milk thistle or cardus marianus is a typical ruderal plant. It is part of the communities called cardinal: communities of large herbaceous, robust, high plants, where composites predominate, family where this plant is included.

milk-thistle2The milk thistle (Silybum marianum) is very tasty in salad. There was a time when it was cultivated for human consumption.

We can often find the milk thistle at roadsides where livestock go by, because the excrements enrich the land, creating a soil more suitable for its development. Due to its thorns, the milk thistle is not consumed by animals, which prefer other plants, allowing the thistle to grow better.

milk-thistle1To differentiate it from other thistles, it is necessary to have a look at the flower which is large and purple, with long, interesting thorns. When only the leaves are present and there are no flowers, they can be differentiated from other thistles by looking at its characteristic white vein on the leaf. The epithet Milk and Marianus (from its name cardus marianus), refers to a medieval legend that said that the Virgin Mary was feeding Jesus when a few drops of milk fell on the thistle’s leaves, which acquired its characteristic white veins and were full of medicinal virtues.

The milk thistle focus its virtues on the liver. The seeds contain silymarin and silybin (1.5% to 3%), very effective and active substances for the protection of this organ. For hepatic problems, the seeds are ground and infused, 10-15 g of seeds per day. Nevertheless we must remember that its main virtue is to minimize the appearance of these problems, not to cure them.

Shortly before the current treatment for poisonings by Amanita phalloides, this substance was used as a treatment for the intoxicated person. Silymarin blocks the entry of toxins of the mushroom into liver cells, reducing damage. The researcher who discovered this voluntarily intoxicated himself with the mushroom several times to show his companions the effectiveness of his discovery. Nowadays a very different therapy is used, but silymarin is still used to decrease liver damage.


The flowers of the milk thistle have traditionally been used to curdle milk during cheese making, although the Cynara cardunculus is more commonly used for this. The property of curdling milk is due to the fact that it has substances that attack milk proteins, break their structure and precipitate them. Vegetable rennet is indispensable to prepare cream cheese, so typical in some areas in Spain. To produce the rennet, the thistle flowers are dried in the shade and macerated in water for a variable amount of time (12-24h), then filtered through a cloth or gauze. The resulting brown liquid is added to the milk.

Gastronomically speaking, the milk thistle is quite tasty. It can be consumed in salad after removing the thorns from the edges of the leaf. At the beginning of the 20th century English gardeners already cultivated the plant for these purposes. Nevertheless it is necessary to mention that it usually accumulates many nitrates inside, so it is necessary to collect it in areas where chemical fertilizers aren’t used, and consume it in small amounts.