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Common Rush Plant

What is Common Rush Plant?

Common Rush Plant (deng xin cao, 灯心草), also known as Rush Pith or Medulla Junci, is the stem pith of Juncus effusus L., which is a perennial herb belonging to the Juncaceae family. 

First recorded in the Materia Medica of the Kaibao Period (Kai Bao Ben Cao) around 974 AD, Common Rush Plant is usually found in moist areas such as wetlands, river banks and wet pastures. It is considered an invasive weed in many places, it can be used as a food additive, and it is the raw material used for making tatami.

During late summer and autumn, people will harvest the stems, dry them under the sun, extract their pith, straighten the stem piths, tie them into small handfuls and cut them into pieces for medicinal usage. There are more than 50 kinds of herbal prescriptions that contain this herb.

In Traditional Chinese Medicine (TCM), Common Rush Plant falls under the category of ‘Herbs that drain Dampness’. Such herbs are typically diuretics that can promote the increased production of urine to remove Dampness that has accumulated in the body.

Cold in nature, Common Rush Plant can help individuals who have too much Heat in their body, such as those experiencing a yang excess or a yin deficiency, to restore a harmonious yin-yang balance. Sweet in taste, Common Rush Plant can slow down acute reactions, detoxify the body and has a tonic effect on the body by replenishing qi and blood. In particular, Common Rush Plant targets the Heart, Lungs and small intestines.

Functions and Benefits of Common Rush Plant

Traditional Chinese Medicine (TCM) shows that Common Rush Plant has the following health benefits.

Common Rush Plant can promote urination and drain Dampness. Thus, this herb is often used to treat syndromes of excess Heat, such as hot and painful urinary dysfunction with dark, scanty urination. 

Also, Common Rush Plant can clear Heat from the Heart by directing fire downwards and calming one’s spirit. For example, Common Rush Plant can treat symptoms such as paediatric sleep disorders, irritability, insomnia, restless sleep, as well as symptoms caused by Heart fire with Kidney yin deficiency.

In addition, Common Rush Plant can clear Lung Heat. This herb can thus be used to relieve sore throat. When charred, Common Rush Plant can cool the blood and stop bleeding too.

How to Use Common Rush Plant

The recommended daily dosage of Common Rush Plant is 1 – 3g, when used as a decoction. If used in its fresh form, the recommended dosage of Common Rush Plant can go up to 15 – 30g.

When Common Rush Plant is charred, it can cool blood and stop bleeding. On the other hand, if left unprocessed, Common Rush Plant can promote urination and clear Heat.

To treat insomnia, it is best to use Common Rush Plant when mixed with cinnabar. To use externally, you may stir-bake Common Rush Plant into charcoal and then grind into powder for sprinkling, or pound the fresh product for application.

Common Rush Plant and its supplements may be found in herbal stores and Asian specialty markets.

Cautions and Side Effects of Common Rush Plant

Common Rush Plant should not be used by individuals experiencing Cold or deficiency in the middle jiao or urinary incontinence.

We strongly encourage you to consult your healthcare provider before deciding to add Common Rush Plant to your healthcare routine!


Here is a summary for Common Rush Plant:

  • Herb name (Chinese): 灯心草
  • Herb name (Pin Yin): dēng xīn cǎo
  • Herb name (English): Common Rush
  • Herb name (Botanical): Medulla Junci
  • Origin of species: Juncus effusus L.
  • Part(s) of herb used: Stem Pith
  • Geo-specific habitat(s): Jiangsu, Sichuan, Yunnan, Guizhou
  • Taste(s) & Properties: Sweet, bland; Slightly cold; Administrates the Heart, Lung and Small Intestine Meridians
  • Actions: Promotes urination; Relieves insomnia and canker sores due to internal heat

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