Niu Xi (Radix Achyranthis Bidentatae)

Twotoothed Achyranthes Root (niu xi, 牛膝), also known as Radix Achyranthis Bidentatae, refers to the dry root of Achyranthes bidentata Bl., which is a perennial herbaceous plant that belongs to the Amaranthaceae family. In China, this plant is mainly produced in the provinces of Henan, Sichuan, Yunnan and Guizhou.

In Traditional Chinese Medicine (TCM), Niu Xi falls under the category of ‘Herbs that invigorate the blood’. Such herbs can stimulate the blood flow and aid blood circulation in cardiovascular conditions or menstrual irregularities, as well as to treat acute pains, tumours, cysts and hardened clots caused by blood stagnation.

Neutral in nature, Niu Xi does not affect the yin-yang balance in one’s body.  Bitter and sour in taste, Niu Xi can cleanse the body by clearing Heat, drying Dampness and promoting elimination via urination or bowel movements. Also, Niu Xi can aid digestion and restrain abnormal discharges of fluids from the body, such as diarrhoea or heavy sweating. In particular, Niu Xi targets the Kidneys and the Liver.

Traditional Chinese Medicine (TCM) shows that Niu Xi has the following health benefits.

Niu Xi can invigorate one’s blood, expel blood stasis, unblock meridians and alleviate pain. Thus, this herb is frequently indicated for all kinds of syndromes of blood stasis accumulation, such as amenorrhea caused by stasis, dysmenorrhea, irregular menstruation, postpartum abdominal pain and traumatic injuries. For amenorrhea due to stasis, dysmenorrhea, irregular menstruation and postpartum abdominal pain, Niu Xi is usually combined with blood-activating and stasis-dispelling herbs such as Dang Gui, Chuan Xiong and Hong Hua to enhance its effectiveness.

As Niu Xi can tonify one’s Liver and strengthen one’s tendons and bones, Niu Xi can treat pain and soreness in the lower back and knees due to Kidney and Liver deficiency, atrophy-flaccidity and arthralgia syndromes caused by evasion of Wind, Cold and Dampness.  Also, as Niu Xi can clear Damp-Heat in the Lower Jiao, it is great at promoting diuresis, and can thus relieve stranguria and hematuria caused by Damp-Heat accumulation, as well as edema and dysuria. 

By descending blood and fire, Niu Xi can treat syndromes of fire and Heat flaring up, which are manifested as symptoms such as headache, vertigo, hematemesis, swollen and painful gums, toothache and epistaxis. For headache and vertigo caused by hyperactivity of Liver yang, Niu Xi can be combined with Liver-pacifying and yang-subduing herbs to enhance its treatment effects. 

The recommended daily dosage of Niu Xi is 6 – 15g, when used as a decoction. 

To activate blood, regulate menstruation, induce diuresis, relieve stranguria and descend blood and fire, it is best to use Niu Xi in its unprocessed form. To tonify one’s Liver and Kidneys, and strengthen tendons and bones, it is best to use Niu Xi that is processed with wine.

You may find Niu Xi and its supplements, such as pills and powder, in herbal stores and Asian specialty markets.

Niu Xi should not be used by individuals experiencing pregnancy, diarrhoea caused by Spleen deficiency, weak digestive abilities or spermatorrhea. Do not use Niu Xi together with Willowleaf Swallowwort Rhizome (Bai Qian).

We strongly encourage you to consult your healthcare provider before deciding to add Niu Xi to your healthcare routine!

Here is a summary for Niu Xi:

• Herb name (Chinese): 牛膝
• Herb name (Pin Yin): niú xī
• Herb name (English): Twotoothed Achyranthes Root
• Herb name (Botanical): Radix Achyranthis Bidentatae
• Origin of species: Achyrantes bidentata Bl.
• Part(s) of herb used: Root
• Geo-specific habitat(s): Henan, Sichuan, Yunnan, Guizhou
• Taste(s) & Properties: Bitter, sweet, sour; Neutral; Administrates the Liver and Kidney Meridians
• Actions: Relieves menstrual discomfort; Eases back pain, weak knees and difficult urination; Soothes headaches, dizziness and canker sores; Eases bleeding conditions by relieving internal heat

Yang, L., Hou, A. J., Yan, M. L., Xing, X. D., Guo, X. Y., Jiang, H., … & Kuang, H. X. (2019). Investigation of radix achyranthis bidentatae phytochemistry and pharmacology. World Journal of Traditional Chinese Medicine, 5(1), 50-60. [Accessed on 15th August 2023]

Zhang, L., Shi, X., Huang, Z., Mao, J., Mei, W., Ding, L., … & Wang, P. (2020). Network pharmacology approach to uncover the mechanism governing the effect of radix achyranthis bidentatae on osteoarthritis. BMC complementary medicine and therapies, 20(1), 1-12.[Accessed on 15th August 2023]

Zhou, X., Siu, W. S., Zhang, C., Liu, C. L., Cheng, L., Kwok, H. F., … & Ko, C. H. (2017). Whole extracts of Radix Achyranthis Bidentatae and Radix Cyathulae promote angiogenesis in human umbilical vein endothelial cells in vitro and in zebrafish in vivo. Experimental and Therapeutic Medicine, 13(3), 1032-1038.[Accessed on 15th August 2023]