The Medicinal Herb Info site was created to help educate visitors about the often forgotten wisdom of the old ways of treating illnesses. Many of today's drugs and medicines were originally derived from natural ingredients, combinations of plants and other items found in nature.

We are not suggesting that you ignore the help of trained medical professionals, simply that you have additional options available for treating illnesses. Often the most effective treatment involves a responsible blend of both modern and traditional treatments.

We wish you peace and health!


Scientific Names


  • Polygonum aviculare L.
  • Polygonaceae
  • Buckwheat family

Common Names

  • Beggarweed
  • Bird knotgrass
  • Birdweed
  • Cow grass
  • Common knotweed
  • Crawlgrass
  • Doorweed
  • Fen-chieh-ts’ao (Chinese name)
  • Goose-grass
  • Knotgrass
  • Ninety-knot
  • Pien-hsu (Chinese name)
  • Pigweed

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Parts Usually Used

Flowering herb, fresh or dried
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Description of Plant(s) and Culture

Knotgrass is an annual plant; the creeping, prostrate stem bears alternate, sessile, lanceolate leaves that narrow at the base, which is covered by brownish, sheathing, knotlike stipules. At the base of each leaf is a jagged, silvery sheath. The axillary flowers, growing all along the stem, are small, green and white or green with pink or purple margins.

Flowering time is from June to October. Blossoms are followed by brown, three-sided fruits in dried petals.

Other varieties: Smartweed or water pepper (P. hydropiper); Water smartweed (P. punctatum); Lady’s thumb, Doorweed, Heartsease, Heartweed, Pinkweed, Redleg, Spotted knotweed (P. persicaria).
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Where Found

Found in waste places, roadsides, yards, and cultivated soils all over the world. Also found on shores and around salt marshes. Culpeper tells us that Knotgrass or Knotweed grows in every country of this land.
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Medicinal Properties

Astringent, diuretic, hemostatic, vulnerary
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Biochemical Information

Volatile oils, silica, mucilage, tannins, and various flavonic derivatives, quercitol, salicylic acid, and kaempferol
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Legends, Myths and Stories

Knotgrass has been used in China as a medicinal for lung ailments since the second millennium BC.

A strong tea held in the mouth for 5 minutes relieves toothache and stops bleeding gums. Prolonged use is said to harden loose, spongy gums and make teeth less sensitive. Helps prevent tooth decay.
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Knotweed is recommended for diarrhea, dysentery, and enteritis. Good for bronchitis, whooping cough, jaundice, and lung problems. As a blood coagulant, it is useful for all forms of internal bleeding, including stomach ulcers, snake bites, rheumatism, kills worms, blood purifier, inflammations, swellings, toothache, gangrene, canker sores, filthy ulcers, sores, venereal sores, ear infections, pyelitis, and piles. The fresh juices can be used to stop bleeding from the gums, wounds and from nosebleeds. Knotgrass has been successfully used for cholera infantum, a serious condition with simultaneous vomiting and diarrhea in infants. Taken regularly, the tea or the tincture dissolves gravel and stones.
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Formulas or Dosages

Infusion: steep 4 tsp. flowering herb in 1 cup water for 5 minutes. Take 1 to 1 1/2 cups a day, a mouthful at a time, as needed.

Decoction: use 4 tsp. flowering herb in 1 cup water. Take a mouthful at a time, as needed. For stomach and intestinal problems, take 1 to 1 1/2 cups a day; for lung problems 1 1/2 cups a day.

Tincture: take 10-20 drops of knotgrass with 5-20 drops of shave grass in water, three or more times a day.
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Buy It! The Herb Book, by John Lust, Bantam Books, 666 Fifth Avenue, New York, NY. copyright 1974.

Buy It! Chinese Medicinal Herbs, compiled by Shih-Chen Li, Georgetown Press, San Francisco, California, 1973.

Buy It! Culpeper’s Complete Herbal & English Physician: Updated With 117 Modern Herbs, by Nicholas Culpeper, Meyerbooks, publisher, PO Box 427, Glenwood, Illinois 60425, 1990, (reprint of 1814)

Buy It! Planetary Herbology, by Michael Tierra, C.A., N.D., O.M.D., Lotus Press, PO Box 325, Twin Lakes. WI 53181., Copyright 1988, published 1992

Buy It! American Folk Medicine, by Clarence Meyer, Meyerbooks, publisher, PO Box 427, Glenwood, Illinois 60425, 1973

Buy It! Secrets of the Chinese Herbalists, by Richard Lucas, Parker Publishing Company, Inc., West Nyack, NY, 1987.

Buy It! Webster’s New World Dictionary, Third College Edition, Victoria Neufeldt, Editor in Chief, New World Dictionaries: A Division of Simon & Schuster, Inc., 15 Columbus Circle, New York, NY 10023

Buy It! An Instant Guide to Medicinal Plants, by Pamela Forey and Ruth Lindsay, Crescent Books (January 27, 1992).

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