Erxian Tang: Two Immortals Decoction

by Subhuti Dharmananda, Ph.D., Director, Institute for Traditional Medicine, Portland, Oregon

The Two Immortals Decoction has an intriguing name. Who are these immortals? And, why is the formula named after them?

Two (er = two) of the formula ingredients in the six herb formula Erxian Tang have xian in their names: curculigo (xianmao; see Figure 1) and epimedium (xianlingpi; see Figure 2), explaining, most simply, how the formula got its title. There are other formulas named in this way, such as Erdong Tang, comprised of ophiopogon (maimendong) and asparagus (tianmendong). But, in that case, the name is not so interesting: dong (= winter) was used in the name for ophiopogon because the plant doesn't wither in winter; it was used in the name for asparagus because of the similarity of its uses to that of ophiopogon. In the case of curculigo and epimedium, the common term xian (= immortal) applies to an important part of Chinese culture.

Xianmao was named in the Bencao Gangmu (by Li Shizhen; 1596) as one of the herbs believed to contribute to immortality (1). This property was described as making the body lighter when taken over a period of time (the mao portion of the name refers to the spear shaped leaves). Xianlingpi alludes to the immortals' intelligent nature (pi refers to the spleen, which is, according to the Chinese, the source of wisdom); this name appears to have been a popular designation for the herb that was originally called yinyanghuo (which describes it as an aphrodisiac).

The Taoists who undertook the effort to become immortals were thought to become lighter and lighter, until they could float up into the clouds. This, and other changes, was brought about by their meditations in seclusion and their ingestion of elixirs prepared in secret. The Chinese character for xian (immortal) is the combination of man and mountain: it refers to the mountain dwelling Taoists.

Around 100 B.C., a poem about attaining immortality, the ode Yuan Yu (Journey to Remoteness, or Roaming the Universe) was written. It depicts the transition to immortality thus (2):

Having heard the precious teaching, I departed,
And swiftly prepared to start on my journey.
I met the feathered ones at Cinnabar Hill,
I tarried in the ancient Land of Deathlessness.
In the morning, I washed my hair in the Hot Springs of Sunrise,
In the evening, I dried myself where the suns perch.
I sipped the subtle potion of the Flying Springs,
And held in my bosom the radiant metallous jade.
My pallid countenance flushed with brilliant color,
Purified, my jing began to grow stronger;
My corporeal parts dissolved to a soft suppleness,
And my spirit grew lissome and eager for movement.

The writer then describes clinging to a cloud and riding aloft on it, to "the very spheres of the storied heavens" where he entered the court of the Supreme Ruler (Heavenly Emperor), and entered the precincts of the Great Beginning. The various stops along the way, at Cinnabar Hill, Land of Deathlessness, Hot Springs of Sunrise, etc., are the meditational goalposts of his efforts at cultivating his qi and jing. The potion of the Flying Springs is his alchemical, possibly herbal, concoction of immortality; the jade was his amulet of spiritual freedom. Though he started out pallid, his complexion became radiant, and his jing (essence) was supplemented. Then his physical weight dropped away, allowing his spirit to roam free. The removal of corporeal weight is one of the signs that immortality is at hand and is mentioned frequently in the Shennong Bencao Jing (3) as a property of herbs. Epimedium, listed in that text, was not included among the herbs that caused the body to become light, but it apparently gained a reputation as valuable for the immortals at some later date. But, even in the ancient text, it was noted the epimedium boosts the qi and strengthens the will, important contributors to the path to immortality.

Stories of the immortals date back to around 400 B.C. and continued until the 20th century (see Figure 3, cover of a modern Taoist book on immortality), though their heyday was during the period from the Han Dynasty up to the first part of the Tang Dynasty. The early Chinese Emperors were quite interested in gaining this immortality; lacking the time and discipline to pursue the Taoist mental and physical exercises, they supported the study and development of elixirs that they could take. After the 8th Century A.D., there was more emphasis on down-to-earth practicality and only a few Taoists still spent time seeking immortality.


The term xian, with the meaning of an immortal, appears in several other herb names, aside from xianmao and xianglingpi, including (4):

xianhecao: agrimony (a hemostatic)
xianmaoshen: scorzonera (an antirheumatic)
xianrenzhang: opuntia (a blood vitalizer)
jiuxiancao: thesium (wind heat dispeller)
tianxianteng: aristolochia (a blood vitalizer)

These herbs have varying uses and their linkage to immortality elixirs is unclear. Dozens of herbs that had names established prior to their use in attaining immortality or named by other methods to designate their origins have been used in the alchemical elixirs. So, this designation is not necessarily indicative of the importance of the herb in relation to this historic use by the Taoists.

The term xian also appears in some names of well-known formulas, such as Xianfang Houming Yin (Immortal's Formula for Preserving Life; Angelica and Mastic Combination), which is not an immortality formula, but one that was said to have been relayed by the immortals. Indeed, there are numerous stories of herb formulas being handed down from or influenced by unusual sources. For example, Tianwang Buxin Dan was said to come from the Heavenly Emperor (tianwang) and Sishen Wan, often translated as Four Immortals Pill, makes reference to the intervention of divine spirits to yield a miraculous recovery. So, the formula Erxian Tang takes part in this ancient tradition of connecting to China's spiritual and mythic icons, even though the author of the formula may have simply noted that xianmao and xianlingpi offered an easy way to name the prescription.


Erxian Tang was developed at the Shuguang Hospital affiliated with the Shanghai College of Traditional Chinese Medicine during the 1960s. It was reported in the college's textbook Fangji Xue (Study of Traditional Chinese Medical Formulas) that was published in 1975 (5).

Erxian Tang was designed as a treatment for hypertension in cases where there was a combination of kidney yang deficiency and deficiency fire of the kidney; two seemingly contradictory conditions. Normally, one expects deficiency fire of the kidney to be associated solely with yin deficiency; in fact, the resulting fire is described as a type of yang excess that arises from the imbalance of yin and yang (the deficient yin doesn't control the yang). A commonly cited formula for treating this condition of yin deficiency fire is Anemarrhena, Phellodendron, and Rehmannia Formula (Zhi Bai Dihuang Tang). When yin and yang are both deficient, one can experience symptoms of each deficiency, which may either vary back and forth between the two, or demonstrate both simultaneously.

The disorder of kidney deficiency with both yang deficiency and deficiency fire may fit the condition referred to in modern medical terms as renal hypertension. This disorder results from limited circulation in the kidneys (renovascular disease), urinary elimination disorders (leading to retention of water and increased vascular pressure), and excessive renin production (a kidney-produced hormone that stimulates angiotensin to increase blood pressure).

In China, moderate hypertension has not been an objective of treatment, as it yields no symptoms. In the West, hypertension (blamed for many heart attacks and strokes) became known as the silent killer because of this lack of symptoms. In recent years, treating even mild hypertension has been considered important. By contrast, patients in China who came for treatment of hypertension usually had very severe and symptomatic cases, with headaches, ringing in the ears, and other signs associated with the TCM categories of wind and internal heat (fire) rushing upward to the head, potential indicators of deficiency of yin and blood. A formula for hypertension, called Tianma Gouteng Yin (Gastrodia and Uncaria Decoction), had been designed just a few years prior to the work with Erxian Tang which treated this syndrome. Its main objectives are to calm wind (with gastrodia, uncaria, and haliotis), clear heat (with gardenia and scute), and nourish the kidney (with eucommia, loranthus, polygonum stem, leonurus, and hoelen).

These symptoms of severe hypertension tended to occur in older people, many of them showing concomitant signs of yang deficiency (e.g., backache, kidney dysfunction, low libido, and chilliness in the legs). Further, laboratory research revealed that yang tonic herbs often had blood-pressure lowering effects, more so than yin and blood tonic herbs. Among the herbs found to lower blood pressure were cistanche, cuscuta, epimedium, eucommia, and morinda (1). The author of the Erxian Tang formula (who is not identified in the literature), combined the primary therapy for yin deficiency fire (anemarrhena and phellodendron) with yang tonics (epimedium, morinda, and curculigo) to produce a unique therapy for hypertension.

The formula is (4):

Erxian Tang
Curculigo 6-15 g
Epimedium 9-15 g
Morinda 9 g
Tang-kuei 9 g
Anemarrhena 4.5-9 g
Phellodendron 4.5-9 g

The first clinical evaluation of Erxian Tang was published in 1962, in which it was reported to be effective in treatment of neurohypertension, renal hypertension, and post-orchiectomy (gonad removal) hypertension (6). A second clinical evaluation, with results published in 1965, indicated that the formula was especially effective in treating stage III hypertension, and for hypertension in patients who had either yin deficiency with deficiency fire (a secondary yang excess) or both yin and yang deficiency (7).

In working with the hypertension patients, some physicians noted that women with menopausal hypertension showed benefits for not only their blood pressure, but also some other menopausal symptoms, such as hot flashes and night sweating. Shanghai, where Erxian Tang was being investigated, is the primary center for research into diseases and disorders that affect women, so this area of application became a focus of clinical investigation.

The formula soon became known as a therapy for menopause when both yin and yang are deficient, with particular application to menopausal hypertension, as depicted in the Shanghai College text. Some modifications of the basic formula were proposed by other authors for treatment of menopausal syndrome with yin and yang deficiency. For example, in Clinic of Chinese Medicine (8), this prescription was suggested:

Curculigo 9 g
Epimedium 9 g
Morinda 9 g
Tang-kuei 9 g
Rehmannia, cooked 9 g
Anemarrhena 9 g
Phellodendron 9 g
Ligustrum 9 g
Eclipta 9 g

This is Erxian Tang with Erzhi Tang (ligustrum plus eclipta, a formula for yin deficiency often recommended for menopause) plus rehmannia, an ingredient that seems missing from Erxian Tang, when compared with traditional kidney tonic formulations.

Erxian Tang also generated interest among fertility researchers who tested its effects on male infertility. Like the female syndrome, this male syndrome was thought to be associated with kidney deficiency. Normally, male reproductive troubles are noted in the Chinese literature to be impotence and spermatorrhea, which are associated with yang deficiency. Those conditions are treated by formulas such as Zan Yu Dan (Reproduction Aiding Pill), which includes curculigo, morinda, and epimedium along with other warming yang tonics: eucommia, allium seed, cnidium fruit, aconite, and cinnamon bark (4). These yang tonics are also used in treatment of low sperm motility (observed only by modern microscopic methods), which is interpreted as being the result of qi and yang deficiency. But, in many cases of male infertility, another important problem is that the semen becomes less fluid, resulting in failure to disperse the sperm. This inadequately liquefied semen is a characteristic of yin deficiency, which results in drying and thickening of fluids. A standard formula for such problems is Zhi Bai Dihuang Wan (Anemarrhena, Phellodendron, and Rehmannia Formula). Combining the yang tonics and the deficiency heat herbs as done in Erxian Tang appeared to potentially address the male fertility disorder. Erxian Tang and formulas with similar ingredients have been applied to these problems in both laboratory and clinical settings and deemed effective (9, 10, 11). An example of a modified version of the formula used for this problem is Yehua Tang, made from Erxian Tang with rehmannia, moutan, salvia, ophiopogon, trichosanthes root, scrophularia, red and white peony, lycium, pumpkin seed, and plantago seed (11, 12). Plantago seed and pumpkin seed are remedies for prostatic swelling.

Erxian Tang serves as an example of the evolving traditional Chinese medicine system. In this case, a new pattern of herb prescription was utilized, with strongly-warming yang tonics combined with cold, fire-purging herbs. Although combining contrasting herbs has been tried before, such as in the well-known Zuojin Wan (Pill of Left Gold) comprised of the hot spicy evodia and the cold bitter coptis, the application of this approach to balancing the kidney yin and yang is rare. The therapy appears to be effective both for its original indication, treatment of hypertension (a modern diagnosis) and for some other applications, such as menopausal syndrome and male infertility. It has also been suggested as a treatment for mild schizophrenia, pyelonephritis, nephritis, and urinary tract infection (5, 6, 7).


  1. Hsu HY, et al., Oriental Materia Medica: A Concise Guide, 1986 Oriental Healing Arts Institute, Long Beach, CA.
  2. Needham J, Science and Civilization in China, volume 2, 1974 Cambridge University Press, London.
  3. Yang Shouzhong (translator), The Divine Farmer's Materia Medica, 1998 Blue Poppy Press, Boulder, CO.
  4. Huang Bingshan and Wang Yuxia, Thousand Formulas and Thousand Herbs of Traditional Chinese Medicine, 1993 Heilongjiang Education Press, Harbin.
  5. Bensky D and Barolet R, Chinese Herbal Medicine: Formulas and Strategies, 1990 rev. ed., Eastland Press, Seattle, WA.
  6. Dong Zhilin and Jiang Jingxian, 100 Famous and Effective Prescriptions of Ancient and Modern Times, 1990 China Ocean Press, Beijing.
  7. Chang HM and But PPH (editors), Pharmacology and Applications of Chinese Materia Medica, 1986 World Scientific, Singapore.
  8. Zhang Enquin, Clinic of Traditional Chinese Medicine, 1990 Publishing House of Shanghai College of Traditional Chinese Medicine, Shanghai.
  9. Zhou Jiale and Cai Xiucai, Treatment of 70 cases of male infertility by Chinese medicine, Jiangxi Journal of Traditional Chinese Medicine 1989; 20(3): 15.
  10. Fang Zhaoqin, Zhang Bona and Xu Fengxian, Effect of Erxian Tang on ultrastructure and succinate dehydrogenase of spermatids and sperms in old rats' testes , Reproduction and Contraception 1993; 13(1): 62-64.
  11. Tan Fengsen and Tang Hongya, Treatment of male infertility due to nonliquefaction of semen, Shanghai Journal of Traditional Chinese Medicine, 1989; (11): 25-26.
  12. Jin Weixin, et al., Treatment of 248 cases of male infertility with Shengjing Tang and Yehua Tang, Journal of Traditional Chinese Medicine 1988; 29(5): 363-365.

March 2002

Figure 1: Curculigo orchioides.

Figure 2: Epimedium sagittatum.

Figure 3: A recent book describing the immortals.