Medicinal plants

Meadow knotweed (Polygonum bistorta) - healing effects and application

Meadow knotweed (Polygonum bistorta) - healing effects and application

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Meadow knotweed was popularly known as dragon root - its roots were reminiscent of a tangle of snakes and it was considered a remedy for snake bites. In fact, the swamp plant contains a lot of tannins, and these act against inflammation and help with wound healing.


  • Scientific name: Polygonum bistorta
  • Common names: Snake knotweed, snake knotweed, snake root, snake root, dragon root, otter root, crab root, sheep tongue, mutton tail, lamp cleaner, toothbrush and leek
  • Parts of plants used: Root, rhizome and leaves
  • application areas:
    • Astringent in diarrhea
    • Inflammation in the mouth and throat
    • Bloating and digestive problems
  • ingredients: Around 20 percent catechin and tannin genetics. The root contains a lot of carbohydrates, the root and leaves contain potassium, phosphorus, magnesium, calcium and iron.

Effects - tannins

The medicinal effects of snake knotweed are mainly due to its high tannin content. In the plant they protect against putrefaction, and they also show bioactive effects in humans. Tannins compress living tissue on the surface and form protective membranes.

They contract and dry out, thereby removing the microbes that colonize the skin or mucous membrane, the food and making it difficult for bacteria such as fungi to penetrate tissue. They also interact with bacterial proteins. In this way they inhibit inflammation, the contraction of the tissue stops capillary bleeding and the wound secretion decreases.

This is how tannins work against inflammation in the gastrointestinal tract as well as in the mouth and throat, accelerate the healing of wounds and minor burns. They relieve mild diarrhea by clogging. Tannins are also used for detoxification. They dissolve heavy metal ions and alkaloids from their compounds and thus neutralize their toxic effects.

Side effects and interactions

In high doses, tannins induce nausea and can cause inflammation of the stomach (instead of fighting it). A continuous intake of tannins in high doses can damage the liver. The substances make it more difficult for iron to be absorbed. People who already have an iron deficiency should avoid tanning agents.

Some people are sensitive to tannins. Even with small amounts, they develop a nausea. Taking knotweed and medication orally at the same time can reduce the effectiveness of the medication, as the tannins can prevent the body from taking the medicine. To avoid this, you should consume knotweed no earlier than one hour after taking such preparations.

Meadow knot in complementary medicine

The roots and leaves of the medicinal plant are well tolerated with the restrictions mentioned. Therefore, teas from the roots are suitable as a supplementary measure in the treatment of gastrointestinal diseases, inflammatory diseases and wound healing.

Snake knotweed in naturopathy

Naturopathy uses knotweed as a remedy for diarrhea, flatulence and in general, to improve digestion and for inflammation in the mouth. Occasionally, snake knotweed is recommended under the keyword naturopathy for cancer prevention and for the treatment of tumors. Such effects have not been proven.

Meadow knot in folk medicine

In European medicine, the plant has been and is used to stop internal and external bleeding, against the symptoms of pulmonary tuberculosis and externally against ulcers, injuries and hemorrhoids and inflammation of the gums.

Applications in traditional medicine

In folk medicine, the roots and leaves were boiled and drunk as tea against diarrhea and internal bleeding. The liquid extract was used regionally for gargling and rinsing the mouth and throat in case of inflammation or as a healing bath, soaked envelopes and pads against ulcers such as skin injuries.

Traditional Chinese medicine for snake bites

Chinese folk medicine uses knotweed plants against: bloody diarrhea, acute intestinal inflammation, inflammation of the respiratory tract, severe cough, and against hemorrhoids. As in folk medicine in Europe, knotweed is also used in China as a remedy for snake bites.

Meadow knotweed - phytotherapy and nutritional supplements

In addition to the tannins, dragon's root contains minerals such as potassium, phosphorus, magnesium, calcium and iron, so it is also suitable for a balanced diet - with the restriction that the tannins make it difficult to absorb some minerals.

Leaves and roots can be used well as culinary herbs. However, you shouldn't make the main ingredient, as the amount of tanning agents quickly becomes "too much of a good thing". The leaves fit in leafy salads or wild vegetables, for example with Giersch or dandelions. You can also cook them and use them as a substitute for spinach. The root provides carbohydrates and is suitable for patties. All you have to do is slice the roots (previously dried in the sun), soak them in water overnight or marinate them in oil and fry them the next day.

External use: Against gum inflammation and hemorrhoids

The main drug of the meadow knotweed is the root. From this you make a tea or liquid extract. The water must never boil, as this kills the active ingredients. The root soaks in lukewarm water for several hours to release the medicinal substances. For this, use six grams of the root in 100 milliliters of water and let the drug steep for six hours.

To prevent gingivitis, gargle extensively with the mixture and rinse your mouth with it. In the case of hemorrhoids, skin injuries or skin inflammations, place soaked compresses on the affected areas for about 15 minutes and / or wash them thoroughly with the extract.

Internal use: Against gastrointestinal complaints

Here, let three grams of the root steep in lukewarm water for six hours, strain and drink two to three small cups a day.

Dragon root and magical medicine

In folk medicine, the belief and real effects of plants flowed together. For example, the meadow knotweed bears names like dragonwort or snake knotweed because of its roots, the knots of which reminded people of the clusters of snakes. The herb was mixed into the feed of cows that did not give milk, believing that the milk would come back.

In magic medicine, people thought in analogies. Something that triggered similar associations was considered a remedy for what was thought to be similar. This is how the snake knotweed should heal snake bites with its roots. The fact that tannins actually detoxify heavy metals and alkaloids may have contributed to this notion.

In Russia, knotweed was supposed to help against the "poison" of rabid dogs. Unfortunately, there is no active ingredient other than vaccination against the rabies virus, and those treated with snake root died. However, the Russians also use the plant against ailments for which it has been proven to help, such as bleeding, indigestion and inflammatory diseases.

Where does the meadow knot grow?

The snake knotweed was also a popular medicinal and culinary herb because it is widespread and common. It is a pointer plant for moisture, grows on wet meadows, in swamps, bogs and on river banks, in floodplains and forest clearings with wet depressions, even in shady courtyards and gardens, on rain barrels and water pipes, in ditches and canals.

In Europe it is found everywhere except in the Mediterranean region with its dry hot summers, and in Scandinavia it avoids the cold regions. In the temperate latitudes it occupies large parts of Eurasia and also populates Morocco.

Collect dragon root

The plant, which is up to one meter high, can be collected from April to autumn. From April to August collect the leaves - the rhizome from September to November when the plant has dried up. The root system knots "like a snake" - hence the name snake knotweed. The plant can be easily recognized in late spring and summer by the pink flower pistons that rise up to 70 centimeters straight.

Store knotweed

You can use the leaves fresh or dry them in an airy place and turn them often so that they do not rot. Cut the rootstock into five-centimeter-long pieces, then slice them lengthways and dry at around 40 degrees Celsius, ideally in the oven. The best way to store them is in fabric bags or paper bags.

Snake root in the garden

Meadow knot is ideal for a swamp or water garden. He needs a well-drained surface with a lot of humus, permanent moisture, lots of nitrogen and minerals. He likes sun and penumbra. Ideally, a place in the riverside zone of the garden pond, but also on a rain barrel or on the floor with a regularly used tap.

Pregnant and lactating women - be careful

There is no reliable evidence of how knotweed consumption affects mothers during pregnancy and lactation. Therefore, you should avoid the dragon root at this time.

Which dose is suitable?

The appropriate dose of knotweed root depends on factors such as age and general health. So far there is not enough scientific information to generally recommend an adequate dose of dragonwort. Check with your doctor if you want to exceed two to three small cups of tea a day. (Dr. Utz Anhalt)

Author and source information

This text corresponds to the requirements of the medical literature, medical guidelines and current studies and has been checked by medical doctors.


  • Karl Hiller; Matthias F. Melzig: Lexicon of medicinal plants and drugs in two volumes. Second volume L to Z. Heidelberg-Berlin, 1999
  • Intisar, Azeem et al .: Anticancer Constituents and Cytotoxic Activity of Methanol-Water Extract of Polygonum Bistorta L., in: African journal of traditional, complementary, and alternative medicines: AJTCAM, Volume 10, Issue 1, Pages 53-59, 2013 , ajol
  • Tariq, Akash; Mussarat, Sakina; Adnan, Muhammad et al .: Ethnomedicinal Evaluation of Medicinal Plants Used against Gastrointestinal Complaints, in: BioMed Research International, Volume 2015; 14 Pages, ArticleID 892947, 2015, hindawi

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