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REHMANNIA EIGHT FORMULA
AND ITS VETERINARY APPLICATIONS:
Treating aging animals

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

Animals, like people, suffer from a variety of degenerative conditions with aging, though the incidence rates for specific age-related ailments may differ.  For example, while the degenerative disorder that most frequently leads to premature death in humans is cardiovascular disease, there is a far lower incidence in animals, with some tendency, instead, to renal disorders.  Aches and pains, especially of the lower limbs and lower back, are common to both humans and animals; some breeds of dogs have very high incidence of these problems relatively early in the aging process due to structural features that contribute to cumulative stress on joints.

There is a Chinese herbal combination that fits the requirements of many aging animals, especially the most common pets—dogs and cats—known commonly as Rehmannia Eight Formula.  It sometimes goes by the Chinese names Bawei Dihuang Wan (Pill of Eight Ingredients Headed by Rehmannia), but more commonly by Jingui Shenqi Wan (Pill to Support the Qi from the Golden Cabinet).  Although it is commonly described as a pill (wan), it is also used in the form of a decoction (boiled tea; tang) or a dried decoction (powder extract).

This article will describe the Rehmannia Eight Formula in some detail; additional information can be sought in articles about some of the individual herb ingredients and related formulas.  It is hoped that, throughout these descriptions, veterinarians will recognize possible applications for their patients.  Among the most common uses of Rehmannia Eight Formula and its modifications are treatment of kidney diseases, lower limb weakness and pain, chronic skin disorders, and eye disorders.

A fundamental principle to understand in relation to use of this famous formula is that, according to Chinese medical doctrine, the aging process primarily involves weakening of the substance and function of the kidney/liver systems.  In this way of speaking, the terms “kidney” and “liver” do not necessarily have any relation to the organs we describe today, but to a system of correspondence that was developed in ancient China to help explain the working of the body (for more information about this, please Five Organ Networks of Chinese Medicine). The kidney system is understood to be the repository of the fundamental yin, yang, qi, and essence of the body.  Speaking in simple terms, yin and essence both represent the fluid, nutritive aspect of the body; qi and yang represent the functional aspect of the body.  Through aging, both the fluids dry and the functions diminish in intensity.  The kidney system is understood to be closely linked to the liver system; in particular, the yin and essence of the kidney directly nourishes the liver system.  Within the realm of the somewhat broad definitions of these organ systems depicted by traditional Chinese the organs recognized by modern medicine subsist.  Therefore, treatments for the liver/kidney system may be important for the health of the organs we recognize as liver and kidney.   The other body components (e.g., heart, spleen, lung making up the remainder of the five primary visceral systems of traditional Chinese physiology) may also become involved in the manifestation of aging disorders, but the underlying contribution to disease manifests through the kidney/liver.

A listing of the indications, actions, and uses of the formula is the best way to see how it fits into a clinical practice, but it is important also that practitioners understand the ingredients of the formula and the theoretical framework in which they are used.  Rehmannia Eight Formula is described slightly differently among the various texts of Chinese medicine, because there are different ways of interpreting how the ingredients contribute to the action of the prescription.  The following is a representative formulation that can be used as a starting point for discussion of the ingredients and their effects:

The lead ingredient is rehmannia, which is described in the Chinese tradition as a nutritive agent for the kidney and liver systems, nourishing the yin and blood. The remaining herbs of the formula can be understood as supporting the function of rehmannia, with the small amounts of aconite and cinnamon serving as the hallmark of this particular prescription compared to other rehmannia-based combinations.

The characteristics of rehmannia, for which the processed form (shudi) is most often used, are: rich and moist quality, sweet taste, and warming nature.  Rehmannia is not used by itself because of the richness of the herb, which is said to have a “cloying” quality (it is very sweet and moist).  Three of the herbs in this formula help to balance rehmannia: alisma, hoelen, and dioscorea.  These herbs:

• promote the function of the digestive system (thus helping it handle the thick tonic, which is otherwise found somewhat difficult to digest, like a rich dessert);
• get rid of any excess moisture that may already be present (which, when combined with the moist rehmannia, would make an uncomfortable condition); and
• help the kidney system in a manner that enhances the tonic effect of rehmannia, namely by promoting its draining action. 

The three supporting herbs have a slight draining effect and are balanced by cornus, which has a mild astringent effect.  A characteristic of many of the ancient Chinese formulas is the effort to provide counterbalance in the action of ingredients, so that no excessive action occurs.  Cornus also has a nourishing action, less so than rehmannia, but a support to rehmannia’s effect.

Moutan is a type of peony root, derived from the tree peony.  Like the other peonies, such as white peony (baishao or shaoyao) and red peony (chishao), it has a nourishing nature, though less so than the others.  Alisma and moutan are understood to be suitable for clearing heat (sometimes referred to as “fire”) in cases of yin deficiency of liver and kidney.  Moutan, in addition to its function of removing heat from the blood also improves the circulation of the blood.  Disorders of blood heat and stagnant circulation are under the control of the liver system. 

Dr. Dong Yueling described the above-mentioned ingredients of the formula as follows (1):

Cooked rehmannia governs the function of moistening the kidney and repleting the essence.  It is assisted by cornus, which nurtures the liver and the kidney and constrains the essence.  Dioscorea tonifies and benefits the spleen yin and consolidates the essence.  The administration of these three herbs together tonifies the three yin meridians [kidney, liver, spleen].  Further, rehmannia, matched with hoelen, which mildly soaks dry the spleen’s wetness, reinforces dioscorea’s beneficial effect on the spleen.  Alisma clears and purges kidney fire and prevents the greasy-indigestion of rehmannia.  Moutan clears and purges liver fire and inhibits the undesirable excessive warmth of cornus.  Hoelen, alisma, and moutan are all adjutants and messengers; taken together they are purgative [here meaning to clear excess; but not laxative].  The six ingredients moisten and tonify without causing retention of evil, and they purge, but do not damage normal qi.  The tonification and purgative effects of this formula complement each other.

The herbs described thus far comprise one modification of the Rehmannia Eight Formula, called Rehmannia Six Formula (Liuwei Dihuang Wan).  The remaining two ingredients are small amounts of cinnamon twig (today sometimes substituted by cinnamon bark) and aconite.  These two herbs help the kidney system to retain its yang energy.  While rehmannia and cornus nourish the yin and essence and restrain the loss of fluid and essence, cinnamon and aconite invigorate the yang and help prevent the kidney system from losing its warming action.  These herbs may best be described as having the function of returning the poorly rooted yang (“floating yang” which can cause heat sensations and sweating) to its base in the kidneys.  Cinnamon and aconite have a very spicy taste, and this quality is compensated by the sweet nature of rehmannia and the cool quality of alisma. 

The combined action of the formula’s herbs on the yin and yang of the kidney gives rise to the notion that this is a true “kidney qi” therapy.  Kidney qi is the source of vitality.  Sometimes, this qi is referred to as the “mingmen fire” (life-gate fire) or “premier fire;” it is a beneficial fire, not a pathological one, so long as it is properly rooted in the kidney system.  This kidney qi is the ultimate source of qi that invigorates all the other organ systems.

It is understood by China’s physician scholars that this formula has a remarkable design in which several actions are incorporated in a very balanced manner.  As a result, the prescription has a wide range of applications and very little side effects (no side-effects being expected).

Kampo Medicine refers to the prescribing of Chinese herbal formulas by medical doctors in Japan.  Rehmannia Eight Formula is a good example of a Kampo remedy, in that it is mentioned (several times) in both the Shanghan Lun and Jingui Yaolue (a pair of books from the Han Dynasty, written around 220 A.D.).  It is one of the approved formulas in Japan, and it has been popularized as a result of a long listing of potentially valuable applications.

The book Commonly Used Chinese Herb Formulas with Illustrations (2) gives a listing of the Kampo applications for Rehmannia Eight Formula as follows:

1. Nephritis (nephrosclerosis, nephrolithiasis, nephrotuberculosis), pyelitis (nephroatrophy), albuminuria, and edema.
2. Cystitis, cystolithiasis, cystotuberculosis, senile cystoatrophy, prostatomegaly, dysuria, urinary incontinence, and nocturia.
3. Diabetes and urinary incontinence.
4. Cerebral hemorrhage, arteriosclerosis, hypertension, and hypotension.
5. Neurasthenia, amnesia, nocturnal emission, uncontrolled emission, impotence, and inappropriate erection of the penis.
6. Lumbago, sciatica, deformed vertebra, numbness of the legs, and beriberi.
7. Cataract, glaucoma, decrease of eyesight, and keratitis.
8. Eczema, tinea, senile itching, vaginal itching, dry skin, and urticaria.
9. Chronic gonorrhea, rectoptosis, climacteric disturbance and related disorders.

The first indications are related to urinary system disorders (diabetes is included as a cause of frequent urination).  In the original text, the principal applications of the formula were for syndromes that included urination disorders.  Back pain and limb problems were also mentioned in the original text.  The other indications given for the formula are more recent applications, most of them developed during the past century or two.   Some of the newer indications can be predicted on the basis of the herb ingredients and Chinese medical theories. 

In the book, Kampo Treatment for Climacteric Disorders (3), Rehmannia Eight Formula is described as one for “conditions marked by degenerative changes and decline in functions, commonly associated with aging...”  As a major indication, “limpness or pain in the lumbar region or knees” is cited, along with sensitivity to cold, abnormal micturition, and a variety of symptoms such as impairment of vision or hearing, decline in mental abilities, dry itchy skin, and shortness of breath.  The authors claim that the formula “can be more effective than conventional drug therapy in controlling and preventing complications of diabetes, such as peripheral neuropathy, nephropathy, and retinopathy.”  While the focus of their book is on climacteric syndrome (menopause), they also mention conditions affecting men, such as impotence, prostatitis, and prostate hypertrophy as additional applications of the formula. 

In the book Hundred Famous and Effective Prescriptions of Ancient and Modern Times (4), which reveals the practices in China in recent decades, Rehmannia Eight Formula is said to have the following indications:

Insufficiency of kidney yang marked by lumbago, lassitude of the feet, cold feelings in the lower part of the body, cramping sensation in the lower abdomen, difficulty in urination or plenty of urination, impotence, pale and thick tongue proper, weak and fine pulse, as well as cough due to phlegm retention, diabetes, edema, chronic diarrhea...etc.

For the modern indications, the book relates a list somewhat similar in nature though shorter than that given by the Kampo practitioners: chronic nephritis, hypertension, diabetes, prostatic hyperplasia, postpartum retention of urine, pulmonary emphysema, neurosis, menopausal syndrome, and senile cataract.  The inclusion of cough due to phlegm retention among the indications and pulmonary emphysema among the applications comes from the use of the formula to treat fluid accumulations.  The book goes on to mention two clinical trials of the formula, one for treatment of cataract and the other for dysuria (due to prostatic hyperplasia), both are claimed to show positive results.  In Practical Therapeutics of Traditional Chinese Medicine (5), Rehmannia Eight Formula is described as suitable for cases where “injury of yin has led to injury to yang,” with weakness of the lower back and coldness of the extremities.

To sum up, the Advanced Textbook on Traditional Chinese Medicine and Pharmacology (6) offers this description of the formula and its applications:

Kidney is the prenatal basis that houses life-gate fire.  Insufficient kidney yang causes failure to warm and nourish the lower jiao (burner), exhibiting lumbago, weak lower limbs, a cold sensation of the lower part of the body, and lower abdominal spasm.  Kidney yang deficiency also disturbs qi activities and causes fluid stagnation, resulting in difficult urination, edema of the legs, or polyuria if the fluid is not well controlled; disturbance of fluid metabolism causes formation of phlegm, resulting in phlegm-fluid retention syndrome; diabetes occurs when fluids fail to go up.  The therapeutic principle should be warming and invigorating kidney yang…..In this prescription, small dosages of herbs for warming kidney yang are added to herbs that nourish kidney yin, aiming to gradually generate the physiological fire to warm and nourish kidney qi.

Veterinarians will likely take particular note of the indications for renal disorders, including poor control of urination, and low back pain and weak lower limbs that are standard uses of the formula, as well as secondary application for dry, itchy skin, and visual disturbance, in terms of common problems presented in older animals.  Rehmannia Eight Formula (or one of the modifications described below) is frequently prescribed to animals for these disorders.

Rehmannia Eight Formula is traditionally listed in Chinese medical texts as a pill, made by powdering the herbal ingredients, combining them with honey as a binding agent, and then forming into balls.  The formula is commonly made as a modern patent medicine, both in large honey boluses, with one pill per dose, or small pills that are intended to be taken in large quantities.  A common export to the U.S. is small “tea pills.”  The small pills are especially useful for cats, and can be used for most animals.

Rehmannia Eight Formula is often prepared in China as a decoction by boiling the herbs in water for more than half an hour and straining out the herb remnants to provide a sweet tea (the sweet taste is mainly from the rehmannia and cinnamon) with spicy overtones (mainly from the moutan and cinnamon).  Dried decoctions, as typically used in Japan and Taiwan, are provided as a powder or fine granules.  These can be made into teas by mixing in hot water, but they are best used in veterinary practice by hiding within food so as to disguise the herbal material.  Encapsulated or tableted dried decoctions are also available for use. Rehmannia Eight Formula is typically administered either once per day or twice per day for veterinary applications.  Typically, an initial treatment will last for a few days, but up to a maximum of three months (for serious chronic disease).  Follow-up treatment can last for up to a year or even longer, usually in the convenient pill form.

The dosing method for veterinary applications is not well-defined for Chinese herb formulas.  Generally, small animals (e.g., cats and dogs) get a higher dose per unit body weight than humans, and large animals (e.g. horses) get a smaller dose per body weight than humans.  Typical dosing for an average adult human is 24 of the small patent pills per day or 6–9 grams of the dried decoctions for the initial dosing, which, after an initial improvement in symptoms, can be followed up by a maintenance dose as necessary.  Estimates for animals of varying size are as follows (figures have been rounded to typical measurement amounts; the amounts are for a one day dose).

TABLE 1: Estimates of Dosage for Animals.  The estimates are given for use of either the small patent remedy pills or the dried decoctions. 

Rehmannia Eight Formula has been so widely used throughout the history of Chinese medicine that numerous variations have been developed.  It is of value to know of these prescriptions, since they may be more appropriate than Rehmannia Eight Formula for specific cases.  Some of the formulas closest to Rehmannia Eight Formula are displayed in Table 2, made by simply adding two ingredients.

TABLE 2: Variants of Rehmannia Eight Formula Made by Adding Ingredients.

In Plantago and Achyranthes Formula, plantago seed (cheqianzi) helps remove accumulated dampness and achyranthes (niuxi or huainiuxi) nourishes the liver and invigorates blood circulation.  This formula is often used when there is numbness and/or swelling in the legs or feet; a typical application is diabetic neuropathy.  Rehmannia and Schizandra Formula adds schizandra (wuweizi) and deer antler (lurong), which nourishes the essence and astringes essence; this variant is especially used for infertility, impotence, and coldness of the lower body.

TABLE 3: Variants of Rehmannia Eight Formula Made by Deleting or Substituting Ingredients.  The following formulas are usually selected when there are no evident signs of yang deficiency; there may even be signs of the opposing condition, namely the yang is excessive, yielding symptoms of heat.

The most common variant of Rehmannia Eight Formula is Rehmannia Six Formula, made by deleting the two yang invigorating ingredients, cinnamon and aconite.  In the case where the patient suffers from “yin-deficiency fire” (a condition of obvious heat symptoms attributed to the lack of control of the yang by the yin), anemarrhena (zhimu) and phellodendron (huangbai or huangbo), two cold natured herbs, are used in place of cinnamon and aconite.  Alternatively, when the liver yin and blood deficiency leads to disorders of the vision, aconite and cinnamon are replaced by lycium (gouquzi) and chrysanthemum (juhua), two “eye-nourishing” herbs that have a cooling effect on the liver.

Rehmannia Eight Formula and Renal Disorders

In the modern practice of traditional Chinese medicine, Rehmannia Eight Formula and its variants remain key prescriptions for treatment of renal disorders.  For example, in the book Modern Clinic Necessities for Traditional Chinese Medicine (7), both Rehmannia Six Formula and Rehmannia Eight Formula are mentioned as treatments for chronic renal failure.  For Rehmannia Eight Formula, a symptom of cold limbs is said to suggest the need for including the yang invigorating cinnamon and aconite.  Under the heading of chronic glomerulonephritis, both the Rehmannia Six Formula and Lycium, Chrysanthemum, and Rehmannia Formula are mentioned. 

Recent laboratory animal research has suggested that certain Chinese herbs can inhibit the autoimmune attacks that are often a contributor to renal disorders and can inhibit fibrosis that is part of the degeneration of the kidney (8,9).  Two of the main herbs indicated for this purpose are rhubarb (dahuang) and salvia (danshen).  Because of the strong laxative action of most rhubarb preparations, this ingredient is not preferred by practitioners in the West, though the Chinese make use of it because of its reported high rate of efficacy.  On the other hand, salvia is not associated with any adverse reactions and may be utilized along with the rehmannia based prescriptions; it has a reputation for effectively treating age-related disorders (see: The Use of Salvia for Patients with Renal Failure). Salvia may be added as a single herb extract to the base formula, using about 20 grams of salvia extract per 100 grams of formula extract, or the single herb may be administered along with pills of the selected base formula. 

Qi tonic herbs, such as astragalus and codonopsis, are also utilized in modern prescriptions for renal disorders, with the understanding that “deficiency of spleen qi” leads to disorders of the other internal organ systems, irregularities in immune functions, and weakening of the microcirculation; spleen qi deficiency can also lead to mild, persisting edema. As an example, in Clinic of Traditional Chinese Medicine (10), a treatment for chronic nephritis in patients with yang deficiency is made from a Rehmannia Eight Formula base, including astragalus (huangqi), codonopsis (dangshen), and atractylodes (baizhu) to tonify the spleen, and including plantago seed (cheqianzi) and areca seed (binglang) to drain excess moisture.  A similar prescription is suggested for chronic glomerulonephritis in patients with spleen/kidney yang deficiency, using coix (yiyiren) and polyporus (zhuling) as diuretic herbs in place of plantago and areca. For chronic glomerulonephritis in patients with weakness of kidney qi and serious proteinurea, the formula is similar, but astringent herbs are utilized, such as cuscuta (tusizi), lotus seed (lianzi), rose fruit (jinyingzi), and euryale (qianshi).  Alternative rehmannia-based formulas are used for cases in which yang deficiency is not a dominant concern.   For example, in cases of yang hyperactivity associated with deficiency of yin, the text’s recommended base formula for chronic nephritis is Lycium, Chrysanthemum, and Rehmannia Formula, with addition of tortoise shell (guiban) and haliotis shell (shijueming) to nourish the blood and settle the yang, and with addition of eucommia (duzhong) and Uncaria (gouteng) which reduce blood pressure.   The various herbs that might be indicated for modifying the base formula can be added in amounts of about 15 grams of each, as granules.

1. Dong Yueling, The six ingredients headed by rehmannia, Journal of the American College of Traditional Chinese Medicine 1982 (2): 55–63. 
2. Hong-Yen Hsu and Chau-Shin Hsu, Commonly Used Chinese Herb Formulas with Illustrations, 1980 rev. ed., Oriental Healing Arts Institute, Long Beach, CA.
3. Shibata Y and Wu J, Kampo Treatment for Climacteric Disorders, 1997 Paradigm Publications, Brookline, MA.
4. Dong Zhi Lin and Jiang Jing Xian, 100 Famous and Effective Prescriptions of Ancient and Modern Times, 1990 China Ocean Press, Beijing.
5. Wu Y and Fischer W, Practical Therapeutics of Traditional Chinese Medicine, 1997 Paradigm Publications, Brookline, MA.
6. Huang Yarong, compiler, Advanced Textbook on Traditional Chinese Medicine and Pharmacology, volume 2, 1996 New World Press, Beijing.
7. Wang Qi and Dong Zhi Lin, Modern Clinical Necessities for Traditional Chinese Medicine, 1990 China Ocean Press, Beijing.
8. Jin H, Wang A, and Wang Y, Preventive and therapeutic effects of salvia on glycerol-induced acute renal failure in rats, Journal of Chinese Herbs 1997; 22(40); 236–238, 255–256.
9. Hu L, Yu T, and Jia Z, Experimental study of the protective effects of astragalus and salvia on glycerol induced acute renal failure in rabbits, Journal of Chinese and Western Medicine 1996; 34(5): 311–314.
10. Zhang Enqin (editor in chief), Clinic of Traditional Chinese Medicine (I), 1988 Publishing House of Shanghai College of Traditional Chinese Medicine, Shanghai. 

December 2010