Health benefits of Knotgrass

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Knotgrass Quick Facts
Name: Knotgrass
Scientific Name: Polygonum aviculare
Origin North America and Eurasia and is widespread across the temperate regions of the globe
Colors Green when young turning to dark brown to black as they mature
Shapes Achene ovate, usually triquetrous, 2.0-3.5 mm long, 1.3-2.3 mm wide
Taste Bitter, astringent
Health benefits Cancer, Respiratory Health, Heart health, Gingivitis, Antioxidant benefits, Kidney Stones, Skin Health, Chronic Fatigue, Dysentery, Worm Infestation, Kidney Disorders, Good for the Respiratory Tract
Knotgrass, also referred to as common knotgrass is an annual plant related to dock and buckwheat belonging to the Buckwheat family Polygonaceae. Known scientifically as Polygonum aviculare L, the plant goes by several other common names including bird grass, door-weed, goose grass, hogweed, ironweed, knotgrass, knotweed, mat grass, pink weed, polygonum, prostrate knotweed, Ray’s knotgrass, sea knotgrass, small leaved knotgrass, stone grass, way grass, wire weed, yard knotweed, Centinode, Ninety-knot, Nine-joints, Allseed, Bird’s Tongue, Sparrow Tongue, Red Robin, Armstrong, Cow grass, Pigweed, Pigrush, Swynel Grass, Swine’s Grass, Black strap and surface twitch. The plant is widespread across many countries in temperate regions, apparently native to Eurasia and North America, naturalized in temperate parts of the Southern Hemisphere. In India it is found in the Himalayas, at altitudes of 2200-3800 m.

Plant Description

Knotgrass is a low-growing, weedy grass that grows between 10 and 40 centimeters in height. The plant is found growing in trampled areas such as footpaths and animal trails, in lawns, along the edges, in cracks of sidewalks and other paved surfaces, along roadsides, especially in fields of cereal crops, railway embankments, sandy, gravelly, or rocky coastal areas, grassland, disturbed soils of waste areas and gardens. The plant grows well in soils that are compacted, poorly aerated, rich in nutrients, and of all types and textures. Prostrate knotweed also endures soils with a high salt content, high calcium content, and heavy metal contamination. The plant has woody, branched tough, wiry taproot.  Stem is widespread across many countries in temperate regions, apparently native to Eurasia and North America, naturalized in temperate parts of the Southern Hemisphere.


Leaves are alternate, up to 5cm (2in.) long but usually much shorter, their width about 1/3-1/5 of their length, usually broadest near or past the middle, and narrower towards both ends. They are hair less and short-stalked. They are longish-elliptical with short stalks and rounded bases. Upper ones are few and are linear and stalk less. Stipules are fused into a stem-enclosing, translucent sheath known as an ochrea that is membranous and silvery.


Common knotgrass begins flowering in May and depending on conditions, continues to flower into October. Flowers are small, and inconspicuous, 2 mm (1/12 in.) or less long, without petals and with pink or greenish-white sepals and often appear in groups of 2-5 in the axils.


Fertile flowers are followed by conical, finely knobbed, 3-edged achene, shorter than dry perianth, with 3 equally wide sides. It is 2-3 mm (0.078 – 0.118 inch) long, green when young turning to dark brown to black as they mature and are minutely roughened. Seeds are triangular, mostly with parts of the perianth and dark brown.

Health benefits of Knotgrass

Listed below are few of the popular health benefits of knotgrass

1. Cancer

When it comes to finding a treatment for cancer, researchers have turned increasingly to nature. More and more herbs are being evaluated for their anti-cancer properties and their ability to inhibit cancer cell proliferation. Researchers concluded that the phenolic compounds found in the herb exerted a strong antioxidant and anti-tumor effect and may have a wide range of medicinal uses. However, it is early days when it comes to the study of the herb and more research will be needed before its effectiveness can be confirmed.

2. Respiratory Health

Knotgrass has traditionally been used to treat the symptoms of the common cold including congestion and coughs. It is supposed to have natural expectorant properties as well as anti-inflammatory actions that can help free mucus from the system and help people breathe more easily. No studies have been carried out into the effects of the herb on cold symptoms but there is a lot of evidence from traditional use to recommend it works. To treat cold symptoms, sore throat or bronchitis, knotgrass is often prepared in the form of a tea.

3. Heart health

Knotgrass consists of silica and flavonoids which are known to improve the health of the bloods vessels. It helps regulate the blood circulation and reduce stress from the hearth, a continually busy organ, and therefore helping prevent atherosclerosis and heart stroke.

4. Gingivitis

Gingivitis is a gum infection which is considered by pain and inflammation in the gums. It can be a very painful condition and is typically treated with antibiotics. Because of the risk of side effects and growing concerns over antibiotic resistance, researchers have looked at a number of natural remedies for the condition.

Research evaluates the effectiveness of knotgrass against gingivitis in 60 male subjects. Participants in the study used a knotgrass extract as an oral rinse twice a day for two weeks. Results demonstrated that rinsing the mouth with knotgrass considerably reduced gingivitis and the researchers concluded that Polygonum aviculare L. could possibly be used as a supportive treatment for the condition.

5. Antioxidant benefits

Getting plenty of antioxidants into the system form dietary sources is essential to good health. Antioxidants like those found in knotgrass can protect the body from disease and even reverse the damage done to the cells by free radicals that we encounter on a daily basis. Antioxidants can protect us from a number of serious illnesses and perform an anti-aging function that can help us internally and also improve our external appearance.

Studies into the antioxidant activity of knotgrass have recognized a number of powerful substances. These include various flavonoids and phenolic compounds which several laboratory studies have examined. Research concluded that extracts from knotgrass had clear antioxidant effects.

6. Kidney Stones

Knotgrass may also be a useful natural remedy against kidney stones. Kidney stones or nephrolithiasis is a fairly common and extremely painful urinary tract condition that can lead to significant complications. Research was carried out to evaluate the effectiveness of knotgrass on kidney stones in rats. Researchers concluded that the treatment had a significant effect helping to both prevent and treat the condition.

7. Skin Health

Knotgrass may be applied topically to help boost your skin’s health and appearance and to treat various common skin infections. Knotgrass consists of various flavonoids with powerful antioxidant actions. The herb can help with general skin health by making it look stronger, firmer and younger. It may also help to reduce the appearance of wrinkles, fine lines and other signs of aging.

8. Chronic Fatigue

It is said that, common knotgrass has the potential to combat chronic fatigue as well as some of the common symptoms of fatigue such as depression and chronic pain.

Since it is known for its anti-inflammatory properties, researchers guessed that the herb could relieve fatigue symptoms and set out to test the theory on mice. After feeding extracts of the herb to the mice, scientists were able to conclude that treatment with the herb was effective in reducing fatigue because of its ability to suppress neuro inflammation.

9. Dysentery

Knotgrass is used as an antibiotic that kills the bacteria and works by slowing down the movements of the gut. It decreases the bowel movements and shortens the duration of dysentery and provides relief in other symptoms such as abdominal pain, weakness, and fatigue.

10. Worm Infestation

Knotgrass expels the parasites from the body without causing any harm to the host by acting as an anthelmintic. Parasites include roundworms, and flatworms. It also controls the recurrence of these worms and offers relief in other symptoms like weakness, abdominal pain, itchy rashes, loss of appetite and bloody stool.

11. Kidney Disorders

Prostrate knotweed is used as a diuretic and anti-inflammatory. It works on the kidneys by maintaining its proper functioning and increases the amount of salt and water in the body. It also provides relief in other symptoms associated with kidney disorders like pedal edema, high blood pressure, burning micturition etc. It also encourages the urination and expels the fluid from the body. It is the best remedy for removing kidney stones and helps in relaxing the bladder.

11. Good for the Respiratory Tract

Knotgrass consists of silicic acid that may be helpful in strengthening the connective tissue of the lungs and in Europe it has been used as a remedy for pulmonary tuberculosis and chronic bronchitis. In particular, it has been used in conjunction with other long-term therapies.

The herb’s earlier use as a treatment for tuberculosis has now only historical interest. In recent times knotweed is mostly used in teas due to its diuretic and disinfectant properties.

Traditional uses and benefits of Knotgrass

  • Knotgrass is a safe and effective astringent and diuretic herb that is used mainly in the treatment of complaints such as dysentery and hemorrhoids.
  • It is also taken in the treatment of pulmonary complaints because the silicic acid it contains strengthens connective tissue in the lungs.
  • Whole plant is anthelmintic, astringent, cardio tonic, cholagogue, diuretic, febrifuge, hemostatic, lithontripic and vulnerary.
  • It was previously widely used as an astringent both internally and externally in the treatment of wounds, bleeding, piles and diarrhea.
  • Its diuretic properties make it useful in removing stones.
  • An alcohol-based preparation has been used with success to treat varicose veins of recent origin.
  • Leaves are anthelmintic, diuretic and emollient.
  • Juice of the plant is weakly diuretic, expectorant and vasoconstrictor.
  • Applied externally, it is an excellent remedy to stay bleeding of the nose and to treat sores.
  • Seeds are emetic and purgative.
  • Recent research has shown that the plant is a useful medicine for bacterial dysentery.
  • It is a good herbal remedy for removing Kidney Stones.
  • It also cures inflammation of the Urinary Tract.
  • It is beneficial in the treatment of bronchitis, pulmonary edema, and tracheitis.
  • It cleanses the lungs and the kidneys. It keeps the air sacs clean which eases the Breathing.
  • It relieves Inflammation and Infection from the Trachea.
  • It supports the Immune system and shields the body against foreign particles.
  • It clears toxins from the body.
  • Expectorant property of Knotgrass provides relief from Cough and Cold.
  • It removes mucus from the mouth and throat.
  • Antibacterial property protects the Teeth from Tooth decay and treats Gingivitis.
  • Knotgrass rinses the crystalline deposits from the Joints which is the main cause of Joint Inflammation.
  • It improves the Pain from the Joints and cures Arthritis.
  • It enhances the production of Collagen and Elastin which improves the elasticity of the Skin.
  • It reduces wrinkles and gives a glowing Skin.
  • Anthelmintic property of Knotgrass is useful for patients with Intestinal Worms.
  • It cleanses the stomach and alleviates the symptoms like diarrhea and dysentery.
  • To get rid of nosebleed rubs Knotgrass into the nostrils.
  • It provides relief from Painful Menses.
  • It is beneficial for babies with colic.
  • Fresh juice has been found effectual to stay bleeding of the nose, squirted up the nose and applied to the temples, and made into an ointment it has proved an excellent remedy for sores.

Ayurvedic Health benefits of Knotweed

  • Ascaris: Prepare a decoction of Knotgrass leaves. Keep it for 5-10 minutes. Take it thrice a day.
  • Pyelonephritis: Boil one teaspoon of Knotgrass in a cup of milk. Strain. Drink thrice a day for 7 days. Repeat the process, if problem persists.
  • Nose Bleed: Prepare a juice of fresh leaves of Knotweed. Take it twice a day.
  • Ulcers: Make a paste of fresh leaves. Apply locally on the infected skin, twice a day.
  • Jaundice: Make a decoction of Rhubarb root, Water Plantain leaves, Gardenia fruit and Knotgrass leaves. Take it twice a day.
  • Azoospermia: Prepare a decoction of Astragalus root and died Knotgrass. Drink 2-3 times a day. Astragalus increases Sperm’s survival rate and Knotgrass improves the fertility.

Culinary Uses

  • Young leaves and plants can be consumed raw or cooked.
  • It is used as a potherb; they are very rich in zinc.
  • Rather small and fiddly to utilize, they can be used in all the ways that buckwheat is used, either whole or dried and ground into a powder for use in pancakes, biscuits and piñole.
  • Leaves are a tea substitute.
  • In Vietnam, where it is called rau đắng, it is widely used to prepare soup and hot pot, particularly in the southern region.

Other facts

  • Yields a blue dye that is not much inferior to indigo.
  • The part used is not specified, but it is likely to be the leaves.
  • Yellow and green dyes are obtained from the whole plant.
  • Roots contain tannins, but the quantity was not given.
  • aviculare and P. plebejum are occasionally eaten by people as ‘famine food’.

Prevention and control

Knotgrass can be hand weeded and physically removed, taking care to remove all of the roots. It should be noted that if seeds are present when hand weeding, they can easily fall from the pods and onto the ground when the weed is disrupted.

Raking the weed into an upright position prior to mowing well help remove stems and weaken the plant. Again this can cause the seeds to fall, if they are present.

Regular mowing will help prevent seed head production.

Avoid thin or bare areas of lawn by maintaining good turf vigor with the correct turf care practices. These should include regular aeration and applying adequate nutrition.


  • Some members of this genus can cause photosensitivity in susceptible people.
  • People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution if including this plant in their diet since it can aggravate their condition.
  • Avoid use if taking any kind of medications.
  • Pregnant women and mothers who are breastfeeding should avoid using knotgrass.
  • Fresh juice has been used for nose bleed.
  • An ointment made from the plant is an excellent remedy for sores.






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