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Deng Xin Cao (Rush Pith, Juncus)

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Slightly Cold Deng Xin Cao (Medulla Junci Effusi)
Sweet, Bland, Slightly Cold
Medulla Junci Effusi
Tone Marks:
dēng xīn căo
Alt Names:
Deng Cao, Deng Xin
Lamp Wick Herb


  • Promotes Urination and Treats Dysuria (Lin Zheng)
    It is a mild diuretic mainly used for hot painful dribbling disorders or in cases with dark scanty urine usually due to damp heat in the lower jiao.
  • Clears Heart Heat and Drains Fire
    Mostly used for childhood nightmares and sleep disorders and infantile crying. Also for insomnia and restless sleep in adults due to excess heart fire with kidney yin deficiency (Heart and Kidneys not communicating).
  • Clears Lung Heat
    For sore throat due to heat in the Lung
  • Cools Blood and Stops Bleeding
    For bleeding and sores due to heat in the blood

Contraindications and Cautions

  • Do not use if there is cold or deficiency in the Middle Jiao
  • Do not use in cases of urinary incontinence

Herb-Drug Interactions

  • None Noted

Toxicity and Overdose

  • None Noted


  • 1.5–2.5 grams in decoction 12
  • 1.5-4.5 grams in decoction 13


  • If charred this herb will cool blood and stop bleeding but if left unprocessed it will regulated water flow and clear heat.
  • This herb is better for dysuria with burning pain than Zhu Ye but less effective for irritability and insomnia in adults.
  • It does not clear small intestine heat thru the urine as effectively as Mu Tong. Mu Tong is bitter and cold while Deng Xin Cao is slightly cold, sweet and bland.

Clinical Studies and Research

  • In a study of 30 cases with chronic nephritis 16 showed complete recovery, 8 had significant improvement, 2 showed slight improvement and 4 had no response. Patients took a decoction of Deng Xin Cao (60grams), and tofu (300 grams) once daily for 30 days.
    Fu Zhou Yi Yao, 1983;(3):30.
  • Synthesis and antialgal activity of dihydrophenanthrenes and phenanthrenes II: mimics of naturally occurring compounds in Juncus effusus.
    J Chem Ecol. 2001 Feb;27(2):257-71.
  • Antimicrobial DNA-binding photosensitizers from the common rush, Juncus effusus.
    Photochem Photobiol. 2002 Jul;76(1):51-6.

This Herb Appears in the Following Formulas: