by Eric Brand

Chuan Niu Xi is a commonly confused medicinal in Chinese medicine. The name Niu Xi generally refers to Huai Niu Xi (Achyranthis Bidentatae Radix), which is distinguished from Chuan Niu Xi (Cyathulae Radix). Huai Niu Xi is rarely confused in the market, but Chuan Niu Xi is very commonly misidentified, especially in the U.S., Cantonese, and Taiwanese markets. In addition to Huai Niu Xi and authentic Chuan Niu Xi, two other items are in common use: Tu Niu Xi (derived from Achyranthes longifolia Mak., A. aspera L.), and Wei Niu Xi (derived from Strobilanthes forrestii Diels).

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These medicinals are traditionally thought to have similar but different actions. Huai Niu Xi is the most commonly used Niu Xi product, and Huai Niu Xi will typically be dispensed whenever Niu Xi is called for unless one of the other forms is specified. Huai Niu Xi quickens the blood and frees menstruation, supplements the liver and kidney and strengthens sinews and bones, disinhibits urine and frees strangury, and conducts fire and blood downward.

Chuan Niu Xi is similar in action to Huai Niu Xi. However, it is more effective for quickening the blood and transforming stasis, and lacks the ability to supplement the liver and kidney and to strengthen the sinews and bones. Chuan Niu Xi lies at the center of the confusion when it comes to medicinal authentication and substitution.

Tu Niu Xi clears heat and resolves toxin in the treatment of painful swollen throat, and it quickens the blood and disperses stasis in the treatment of amenorrhea and painful wind-damp impediment (bì) pain. Tu Niu Xi, also known as native achyranthes, is comparatively rarely used in Chinese medicine.

The final form, Wei Niu Xi, is often considered to be an adulterant or improper substitute; it is commonly confused because it also goes by the name Chuan Niu Xi. It is rarely used in mainland China, but it is very common in Taiwan and the West. It also tends to show up in Hubei province and Sichuan province in China. It is said to quicken the blood, clear heat, and free urination, but it is not nearly as well established as the other medicinals.

A top herbal pharmacy professor at China Medical University in Taiwan, Dr. Chang Yung-Shiun (pronounced Zhang Yong-Xun 張永勳, recently did a study on Taiwanese granule formulas containing Niu Xi. By using TLC analysis, he was able to assess marker chemicals that could be used to determine whether the Niu Xi in the product was derived from Huai Niu Xi, Chuan Niu Xi, or Wei Niu Xi.

In Dr. Chang’s research, 60 samples from eight granule companies were tested. A total of ten Niu Xi-containing formulas were assessed; it should be noted that not all formulas were produced by all manufacturers. The 60 samples included the following formulas: Du Huo Ji Sheng Tang (Pubescent Angelica and Mistletoe Decoction), Shu Jing Huo Xue Tang (Channel-Coursing Blood-Quickening Decoction), Ji Sheng Shen Qi Wan (Life Saver Kidney Qi4 Pill), Yu Nu Jian (Jade Lady Brew), Bai Zi Ren Wan (Arborvitae Seed Pill), Xue Fu Zhu Yu Tang (House of Blood Stasis-Expelling Decoction), Ba Xian Tang (Eight Immortals Decoction), Huan Shao Dan (Rejuvenation Elixir), San Bi Tang (Three Impediment Decoction), and Zhe Chong Yin (Thoroughfare Beverage). Out of 60 samples, only four samples contained Huai Niu Xi. No samples contained authentic Chuan Niu Xi. The remaining 54 samples contained Wei Niu Xi, the local substitute medicinal.

I was fortunate to attend the pharmacy conference where Dr. Chang presented his research, and his presentation also included a very comprehensive assessment of lab studies that analyzed the different Niu Xi products based on their ability to relieve edema in animal models, as well as their effects on platelet aggregation, blood pressure, and pain. These parameters were essentially designed as a means of using biomedical lab testing to assess the relatively potency of each type of Niu Xi’s traditional effects.

While it is difficult to draw solid conclusions of traditional effects based on animal research using biomedical models, the results nonetheless helped to illustrate the differences between the pharmacological effects of the various Niu Xi products. According to Dr. Chang’s research, Huai Niu Xi had the best effect on relieving pain, reducing inflammation, and lowering blood pressure. Authentic Chuan Niu Xi was the second-best product for these effects, but it had the best performance on platelet aggregation. Wei Niu Xi was inferior and Dr. Chang et al.’s research suggests that it may not be a suitable Niu Xi product for clinical use (published in the Journal of Chinese Medicine, 8 (3): 165-167, 1997).

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