WHITE PEONY, RED PEONY, AND MOUTAN:
Three Chinese Herbs Derived from Paeonia
The Ranunculacea family yields numerous important Chinese herbs (1), including aconite, anemone, cimicifuga, clematis, coptis, and the peonies (Paeonia). The underground parts-roots or rhizomes-of this group of plants are utilized in making medicines. The genus Paeonia is named for the most ancient Greek god of healing, Paeon, who was known as "the physician of the gods." He was said to have used this plant for medicine. In China, peony is mentioned in the most ancient texts, having been used as a flavoring for food. It has been relayed that Confucius said: "I eat nothing without its sauce. I enjoy it very much, because of its flavoring."
There are two species of Paeonia that are particularly important to Chinese medical practice, Paeonia lactiflora (see Figure 1), which is the primary source of both white peony (baishaoyao or simply baishao) and red peony (chishaoyao or simply chishao), and Paeonia suffruticosa (see Figure 2), the source of moutan (mudanpi).
Modern Chinese herb authorities have grappled with the issue of differentiating the properties and applications of the peony herbs. A clear and consistent picture does not immediately arise because the modern depictions of these herb materials, as found in most materia medicas and Chinese herbal guidebooks, have some discrepancies. An attempt to sort out the conflicting reports is attempted below to the extent possible with the available information.
Peony is known simply as shaoyao when not distinguishing between red and white peony; shao is the term referring to the peony plant, while yao means medicine; hence shaoyao means: the medicine made from peony. Red peony is the whole peony root with its reddish thick outer bark (epidermis) included; white peony is the peeled root; the bark is stripped off to reveal a powdery white to pink underlayer. The way in which white peony is produced is described in the Advanced Textbook on Traditional Chinese Medicine and Pharmacology (6): "The root of the three or four year old plant is dug and collected in summer and autumn, washed clean with the rhizome and fibrous roots [rootlets] removed, and the rough epidermis scraped off, cooked slightly in boiling water, and finally dried in the sun." By contrast, red peony is produced simply by drying in the sun the root that has the rhizome and rootlets removed (see Figure 3).
Peony (shaoyao) was listed in the Shennong Bencao Jing (ca. 100 A.D.) with a single entry. It was described as being bitter, treating evil qi and abdominal pain, eliminating blood stasis, breaking hard gatherings, promoting urination, and boosting the qi (2). In the Tangye Bencao, (ca. 1248), peony was mentioned specifically as a treatment for abdominal pain (3), an indication retained today.
It is unclear how early the whole root (red peony) and peeled white root (white peony) were differentiated, but certainly this was accomplished by the time of the Bencao Gangmu (published 1596). In the translation of the Yinhai Jingwei (10) an ophthalmology text that was probably produced in the 16th century around the same time as the Bencao Gangmu, the two herbs are mentioned:
baishaoyao: bitter, salty, cold. It enters the liver conduit. It can supplement the spleen and diminish the liver qi. It can nourish the liver blood and drain liver fire. When the liver is depleted, and the fire weak, it can not be used.
chishaoyao: bitter, acrid, cold. It enters the liver conduit. It can disperse the blood, and it can make the blood flow. It removes redness of the skin, and stops pain.
Here, there is already a distinction that white peony supplements, while red peony disperses. The caution about the use of white peony is reflected in modern texts, such as Chinese Herbal Medicine Materia Medica (4), which states: Use with caution in cases of diarrhea due to cold from deficiency, and in patients with weak yang and cold from deficiency."
In the translation of Yixue Zhuan Xin Lu (Heart Transmission of Medicine, 11), a book published in the latter half of the 19th century, there is a distinction between baishao and chishao:
baishao treats abdominal pain, and, because it is able to supplement and astringe as well, it also eliminates vexatious heat from the upper part of the body. chishao frees the flow of blood stasis and, because it is able to disperse and drain as well, it also disinhibits the lower abdomen.
The distinction between supplementing (for baishao) and dispersing (for chishao) is again prominent. The action of red peony to "disinhibit" the lower abdomen probably refers to the diuretic action, as depicted in the Shennong Bencao Jing. Further, peony was said to have the ability to drain excess, as mentioned in the Tang Bencao, while distinguishing the action of peony from that of rehmannia and phellodendron, which were said to replenish the deficiency of the kidneys (3). The statement probably also reflects the ability to make blood flow, described in Yinhai Jingwei, which refers to menstrual bleeding that is inhibited.
The ability of baishao to "astringe" is a reflection of the idea, apparently arising during the Qing Dynasty period, that white peony has the sour taste that has astringent effects. The Shennong Bencao Jing only described peony as bitter and gives no indication of astringent action; the other early texts do not mention a sour taste for either red or white peony. To the contrary, the ability of peony, as described in Shennong Bencao Jing to eliminate stasis, break up hard gatherings, and promote urination, appear entirely opposite of an astringent action.
In Smith and Stuart's report on herbs in the Chinese market at the end of the 19th century (5), only shaoyao is listed. Their description of the material, with "pinkish-white color on the outside, and marked with scars and tubercles, and whitish or brownish and semi-translucent in the interior" fits red peony. The scars and tubercles are the break points where rootlets are removed; the distinct interior material is the root beneath the epidermis. It is possible that most herbalists at the time did not firmly distinguish between red and white peony and simply bought the whole roots most of the time.
One can see a degree of confusion about distinguishing the action of the two root materials, though the trend is clear: white peony supplements, red peony disperses, and both treat abdominal pain. As to the modern view of differences between red and white peony, Yang Yifan, in her recent book comparing various Chinese medicinals, writes (7):
Red peony and white peony come from similar plants. Both are cold in nature and enter the blood and the liver meridian. Because red peony is cold and bitter, it is able to reduce liver heat as well as heat in the blood. It has a dispersing property, can invigorate the blood, and remove congealed blood, and is therefore often used in treating pain due to blood stagnation.
White peony is less cold but bitter, so it can clear liver heat or heat in the blood, but its function is weaker than that of red peony. One difference is its sour taste, which results in an astringent property. Cold and sourness may generate and stabilize the yin. As it enters the liver meridian, it particularly nourishes the liver yin and blood. It is an appropriate herb when there is yin deficiency with slight empty heat in the blood. In this situation, the main symptoms are dizziness, dry and burning eyes, irritability, and hypochondriac pain and distention.
Like red peony, white peony can also alleviate pain, but pain caused by liver yin and blood deficiency, in which the muscles and tendons lose their nourishment. This pain is cramping in nature, such as in abdominal pain and cramp after diarrhea, menstruation, labor, or cramp of the muscles of the limbs. Moreover, as white peony has a sour taste, it may stabilize the yin and body fluids and inhibit sweating, so is used for spontaneous sweating and night sweating.
The main differences outlined here are the colder nature of red peony than that of white peony and the sour taste in the white peony that is not in red peony. These particular differences are descriptions contrary to those outlined previously, in which clearing of heat is attributed to white peony rather than red peony, and the sour taste is not ascribed to either (except indirectly implied in one instance of referring to the astringent action).
Although red peony is sometimes obtained from alternative species of Paeonia, such as P. veitchii and P. obovata, the white and red peony can be-and usually are-obtained from the same plant species. The common cultivar is P. lactiflora (lactiflora = white flower). That red and white peony come from "similar plants" is not the best description of the situation; most often, they come from the same plant.
It is easy to provide an explanation as to why the peel of the peony root might contribute a significantly colder property and nature to red peony, something that is lost when producing white peony. Thus, red peony could be more powerful at clearing heat than white peony because of a substance in the epidermis that is particularly potent. From the modern perspective, the epidermis of a root is expected to protect from bacteria and fungus in the soil, and such antibiotic activity would correspond to one aspect of the cold property. One would seek to confirm such an interpretation by comparing the chemical constituents in the epidermis to those in the central part of the root, and by performing pharmacology experiments with the substances found in each part.
Despite the description by Yang of red peony as cold and white peony as less cold, and despite the classification of moutan (where the root bark is the only portion used) as a heat clearing herb, most texts describe all these herbs as being "slightly cold" in nature. In The Illustrated Chinese Materia Medica (8), red peony is listed as "cool, sour, and bitter;" while white peony is described as "slightly cold, bitter, and sour," implying that red peony is either similar-or possibly less cold-in comparison to white peony. So, while the content of the peony root peel might have an impact, it is also possible that its effect in this regard is minor.
The mention of a sour taste in red peony, as portrayed in The Illustrated Chinese Materia Medica, is significant as it is not easy to understand how white peony could have a sour taste that is absent from the whole root (red peony). The actual taste of these two herbs is quite similar (dominated by bitter, the taste mentioned in all the ancient texts). The reference to a sour taste might best be attributed to the tendency of Chinese herbalists to assign tastes according to herb actions (see: Taste and effect of herbs) rather than depicting their actual taste. Red peony has more of a fragrant quality than white peony, probably due to some aromatic constituents in the peel; this fragrant quality is usually associated with descriptions of acrid taste, one mentioned for red peony in the Yinhai Jingwei.
When Yang goes on to distinguish between red peony and moutan in another section of her book, red peony is described as sour, bitter and slightly cold, which, in the portion of her text quoted above, are essentially the same characteristics attributed to white peony, including the sour taste. This would be consistent with the expectation that both white and red peony would share the same taste, but a sour taste in red peony is not included in descriptions of virtually all materia medica books, not even the original description in the Shennong Bencao Jing.
The blood vitalizing aspect attributed to red peony, but ignored for white peony, could also be attributed to something in the peel that is not in the central root. However, one must be somewhat cautious, as the Chinese herbalists have had a tendency to associate the red color of an herb with a blood vitalizing property on the basis of dogma and not necessarily based on obvious effects. Since the peel is of a reddish color, this might account for some of the claim that red peony is more of a blood vitalizer than white peony. Even so, a blood vitalizing function is not prominently mentioned by Yang in her description: red peony is characterized, instead, as treating heat in the blood, while white peony is indicated for deficiency heat in the blood. This commentary about deficiency heat reflects white peony's blood nourishing effects (usually referred to as nourishing the ying, or the nutritive portion of the blood, to distinguish from the wei, the active defensive portion). The tonic property of the central portion of the root (i.e., white peony) should not vanish when the root's epidermis is also present as it is in red peony, so one would expect that red peony would have a similar tonic property, one that seems not to be mentioned.
In sum, despite the efforts to distinguish white and red peony by taste, nature, and effects, the literature is muddled in all these areas, and modern interpretations, based on considering the presence or absence of the root peel, do not readily clarify the picture. Ultimately, white peony and red peony may be more similar than acknowledged.
Moutan was also described in the Shennong Bencao Jing: "Acrid and cold; it mainly treats cold and heat, wind stroke, tugging and slackening tetany, and fright epilepsy evil qi. It eliminates concretions, hardness, and blood stasis lodged in the stomach and intestines, quiets the five viscera, and cures abscesses and sores." The reference to wind stroke, tentany, and epilepsy indicates that the herb was thought to inhibit wind; in modern times, it would be considered internal wind that was generated by deficiency heat affecting the liver. The ability to eliminate hardness and blood stasis in the abdomen is similar to the effects attributed in the same text to shaoyao.
Moutan became particularly popular in the medical literature of the 12th Century. It is included, for example, as an ingredient in the famous Rehmannia Six Formula (Liuwei Dihuang Wan) in a pediatrics text published in 1114 and mentioned in the Zhenzhu Nang (1186), an influential text of the Jin-Yuan medical reform period (4), where it was said to treat "steaming bones when sweating is absent (2)." Moutan was also mentioned in the Tangye Bencao, where it was listed as mushaoyao. It was reputed to treat hemorrhages, nervous disorders, menstrual difficulties, and, if taken for a long time, it would give vigor to the body and prolong life. The character for mu used at that time was the one meaning tree, so this means the medicine was made from tree peony, which is how this herb is often referred to today; later the character mu used for this herb was altered. Moutan is actually a shrub, but through cultivation efforts and a long growing period, it becomes suffruticose: having a woody stem, hence its botanical designation (5).
When Yang compares red peony to moutan, in which both are said to regulate blood circulation, red peony is described as useful for treating excess heat in the blood (and reducing swelling and pain, a condition corresponding to an excess syndrome), while moutan is said to be used for reducing empty heat in the blood. As an elaboration, moutan is particularly suitable for treating the syndrome in which heat disturbs the blood under conditions of yin and blood deficiency (such as fever, skin rashes, and nose bleeding). Based on its importance in treating deficiency heat, one might then expect moutan to have tonic properties. Yet, this is almost never mentioned (except perhaps, in relation to giving vigor to the body with prolonged use). In this apparent contradiction, it might be compared to phellodendron, which is used for treating yin deficiency heat, but is not considered a tonic except in passing in the Tangye Bencao and the Yinhai Jingwei, both of which refer to phellodendron as a kidney tonic.
On the other hand, moutan is not indicated for treating deficiency in the Yinhai Jingwei. Its description is: "Bitter, cold; it enters the kidney conduit. It drains yin fire and yang fire, it can cool the heart and the blood, and it can move stagnating blood. It stops pain." While "yin fire" is a term used to designate a deficiency fire, this text indicates that it is also used for yang fire.
When moutan is depicted as being useful for treating conditions of blood heat with yin and blood deficiency, its action seems quite similar to that of white peony. The Advanced Textbook lists white peony as having these applications:
This list incorporates peony's characteristic of replenishing and astringing the yin-a characteristic shared with cornus (shanzhuyu). The Advanced Textbook explains further:
The liver is a rigid organ that needs nourishment of yin and blood. White peony enters the liver meridian to nourish liver blood and yin, and, therefore, is important for nourishing and soothing the liver. It serves as an agent to counteract stagnant liver qi, relieve muscular spasms and abdominal pain, and calm hyperactive liver yang.
The Advanced Textbook, like some other modern materia medicas, places both moutan and red peony in the category of herbs that clear heat and cool blood. There is a remark about distinguishing them:
Both red peony and moutan can purge heat and cool the blood, and are indicated for diseases caused by heat in the blood and blood stagnation. But moutan produces a better effect in purging heat and cooling the blood, while red peony is more effective in activating blood circulation and removing blood stagnation, it has a weaker action in cooling the blood.
One can see that attempts are made to clearly distinguish the three peony materials, but there are some difficulties encountered in terms of their taste (bitter? acrid? sour?) and the preponderance of certain therapeutic capabilities, such as clearing heat, vitalizing blood, and nourishing blood and yin. Modern texts don't make reference to the ancient claim (in Shennong Bencao Jing) of peony boosting the qi. Since red peony includes white peony (plus the root peel), one would expect it to include the tonic properties found in white peony. Moutan, unlike the other peonies, is classified as being acrid in taste (usually along with bitter); it has a strong aromatic component that is responsible for this quality. The acrid taste in the outer portion of the root materials could be associated with the blood vitalizing activity of moutan and red peony.
All three of the peony materials used in Chinese herbal medicine contain paeoniflorin, a monoterpene glycoside that contributes the bitter taste. In a test of 19 species and 6 varieties of Peonia, paeoniflorin was the major and characteristic component of all of them, while Paeonia lactiflora was one of three (along with P. tenuifolia and P. veitchii) that had the largest amount, with up to 5.8% paeoniflorin (12, 13), though average amounts are about half that, about 3%. The root epidermis appears to contain a similar amount of paeoniflorin as found in the central root, with one study indicating about 2.3%; it has been suggested that removing the root epidermis to make white peony may simply be wasteful (14). There do not seem to be any studies indicating a notable difference in chemical constituents between red and white peony, though this does not rule out the possibility of a significant difference. Laboratory research shows that paeoniflorin has sedative, antispasmodic, and anti-inflammatory effects. The peony roots also contain slightly modified versions of this basic compound, such as oxypaeoniflorin and benzoylpaeoniflorin.
A simple ketone-paeonol-is an additional main component of moutan (about 1.5% of the root bark); there are also lesser amounts of glycoside compounds derived from it, such as paenoside (paeonol glucoside) and paeonolide (paeonol glucose-arabinose); these are found only in Paeonia suffruticosa and other woody species of Paeonia. These compounds have been shown to be antibacterial, antifungal, analgesic, sedative, and anti-spasmodic (16). In addition, it is reported to reduce lipid peroxidation (15). Paeonol is also a key component of cyanchum (xuchangqing), used as an analgesic for arthritis and anti-inflammatory for skin rashes, listed with herbs that dispel wind-damp (17). Paeonol is the aromatic component that gives moutan its characteristic fragrance and acrid taste. It is easily lost during drying and storage; [paeonol content is used as a quality measure for patent preparations for Liuwei Dihuang Wan (Rehmannia Six Formula) and Jiawei Xiaoyao Wan (Bupleurum and Peony Formula) since it is the main volatile component of those widely used formulas. The pharmacological actions of paeoniflorin and paeonol appear to be similar.
It is possible that the differences between the three peony herb materials are quite subtle. All have, to some extent, the attributes of being cold, bitter, heat clearing, and blood vitalizing. In these properties, they are similar to salvia (danshen). Table 1 presents a summary of the issues described above.
Table 1. Issues raised regarding classification and properties of the peony herbs.
|Red peony and white peony are obtained from the same plant, mainly Paeonia lactiflora; sometimes other species are used. The designations red and white do not refer to the flower color (which is white) but to the appearance of the roots, as the root peel is reddish and the interior is white. Moutan is obtained from Paeonia suffruticosa, a related plant that is grown specifically to develop a woody base; the flowers are red, the root bark is used.
|Nature of the herbs
|All the peony materials are slightly cold in nature. In descending order of coldness, according to the implication of modern texts, they are moutan > red peony > peony. These are minor differentiations within the classification of slightly cold.
|Taste of the herbs
|All the peony materials are bitter. The sour taste that is said to be present in white peony is not evident and would be expected to be found in red peony as well. Moutan is described as acrid; red peony may have a slight acrid quality.
|Treatment of deficiency/excess
|White peony and moutan are described as treatments for deficiency heat; while red peony is described as a treatment for excess heat. Still, red peony may possess the tonic properties of white peony and should be as suitable as moutan for treating deficiency conditions, while moutan is not depicted as having any tonic properties.
|Blood vitalizing properties
|All the peony materials promote circulation. The relative strength of this effect as indicated in modern texts, in descending order: red peony > moutan > white peony.
|All the peony materials contain paeoniflorin and its derivatives; it is unclear that the epidermis included in red peony contains anything unique. Moutan contains paeonol, which is not found in red or white peony, and contributes its acrid quality.
|Antispasmodic and analgesic properties
|All the peony materials affect the liver and reduce abdominal pains. White peony is mainly used to nourish the liver and reduce spasms. Red peony and moutan are said to reduce pain associated with blood stasis, with red peony possibly being more effective for this application.
|White peony is described as enriching the liver yin and astringing yin; it is also said to astringe sweating. Moutan, especially if fried until charred, is used to treat bleeding associated with blood heat.
|Introduction of the herbs
|Shaoyao, probably referring to what we today call red peony, was listed in the Shennong Bencao Jing; moutan was listed in the same text with a separate entry. Distinguishing white peony from red peony may not have become common until the 20th century, though the distinction was made at least as early as the 16th century. Red peony has become a frequently used item in modern clinical practice, relied upon for its blood vitalizing and blood cooling properties, similar to salvia.
|Materia Medica category
|White peony is classed with the blood tonics, even though it is described as being a yin tonic and astringent like cornus (classified as an astringent). Red peony is classed either with the blood vitalizing herbs or with the herbs that clear heat and cool blood, the latter being the consistent classification of moutan. There is a separate materia medica section for herbs that clear deficiency heat that might suit moutan, since treatment of deficiency heat is one of its major functions.
Peony, red peony, and moutan are included in numerous formulas, but their role in the combinations may be obscure unless one focuses on those with only a small number of ingredients. In the following tables, traditional formulas with six or fewer ingredients are presented to help reveal the use of the herbs (9). White peony is the most commonly specified for inclusion, although red peony may have been the material actually used in ancient times. Peony was a favored herb of Zhang Zhongjing and included in several small formulas of the Shanghan Lun. In most cases, peony was combined with licorice, as illustrated in Table 2.
Table 2. Antispasmodic formulas with white peony and licorice as key ingredients.
|Peony and Licorice Combination
Shaoyao Gancao Tang
|equal proportions of the two herbs; though sometimes the proportions are varied, usually with more peony than licorice
|This formula is indicated for all kinds of muscle spasms. Peony may be the primary antispasmodic component, while licorice helps peony to alleviate pain, relieve spasms, and reduce inflammation.
| Peony, Licorice, and Aconite Combination
Shaoyao Gancao Fuzi Tang
|peony and licorice are joined by aconite
|Used mainly for spasms in the back and legs, but also for abdominal spasms and pain.
| Scute and Licorice Combination
|peony and licorice are joined by scute and jujube
|For abdominal spasms associated with intestinal disorder, typically with diarrhea.
|Bupleurum and Chih-shih Formula
|peony and licorice are joined by bupleurum and chih-shih
|This formula treats a condition of stagnation, distension, and fullness in the abdominal area that constricts circulation to the limbs, causing the person to experience cold hands and feet. However, the main function is to relax the internal organs and alleviate abdominal distress.
| Cinnamon Combination
|peony and licorice are joined with cinnamon, ginger, and jujube
|This formula is said to regulate the ying and wei qi, being applied when there is muscular aching associated with an acute ailment (e.g., common cold/flu) or abdominal pain.*
*The formula, modified to contain twice the amount of peony (Guizhi Jia Shaoyao Tang) is used for abdominal muscle spasms and pain. Numerous larger formulas are derived from Guizhi Tang by adding one ingredient (e.g., add astragalus, pueraria, aconite, tang-kuei, or maltose), sometimes adding two or more ingredients. The resulting formulas are also used in the treatment of acute ailments marked by muscular spasms and pain.
Table 3. Blood tonic formulas with white peony.
|Coptis and Gelatin Combination
Huanglian Ajiao Tang
|peony, coptis, and scute, with egg yolk and gelatin
|For mental agitation and insomnia due to deficiency of blood; also for fever and bleeding associated with blood deficiency.
|Tang-kuei Four Combination
|peony, tang-kuei, rehmannia, cnidum
|This is the basic blood tonic prescription of Chinese medicine, particularly used for women who suffer from menstrual disorders that result from blood deficiency.
|peony, tang-kuei, cnidium, atractylodes, scute
|A pregnancy formula used to help prevent miscarriage; also for postpartum problems, such as blood deficiency with bleeding.
|Tang-kuei and Peony Formula
Danggui Shaoyao San
|peony, tang-kuei, cnidium, atractylodes, hoelen, alisma
|This was developed initially as a pregnancy formula, used to avoid miscarriage or to treat a variety of pregnancy disorders, but it is also employed as a blood tonic and treatment for mental distress associated with blood deficiency.
Table 4. Formulas with peony and chih-shih, used for stagnation and accumulation syndromes.
|Chih-shih and Peony Formula
Zhishi Shaoyao San
|equal proportions of the two herbs
|Used for abdominal pain, especially postpartum pain associated with qi and blood stasis.
|Platycodon and Chih-shih Formula
|equal proportions of chih-shih and peony, with about half as much platycodon
|Skin eruptions accompanied by stiffness and tension in the abdomen.
|Apricot Seed and Linum Formula
|chih-shih, peony, rhubarb, magnolia bark, linum, apricot seed
|For habitual constipation associated with stomach heat.
|Bupleurum and Chih-shih Formula
|peony, chih-shih, bupleurum, and licorice (note: this formula also listed in table 1)
|This formula treats a condition of stagnation, distension, and fullness in the abdominal area that constricts circulation to the limbs, causing the person to experience cold hands and feet.
Table 5. Formulas with moutan.
|Rhubarb and Moutan Comb.
Shaoyao Gancao Tang
|moutan, persica, benincasa, rhubarb, mirabilitum
|Used for abdominal swellings and pain with constipation and heat syndrome.
|Coix and Persica Combination
|moutan, persica, benincasa, coix
|For suppurative infections with fever.
|Coptis and Rehmannia Formula
|moutan, rehmannia, coptis, cimicifuga, tang-kuei
|For oral ulcerations and swelling and pain in the throat.
|Rehmannia Six Formula
Liuwei Dihuang Wan
|moutan, rehmannia, alisma, cornus, hoelen, dioscorea
|For yin deficiency with slight deficiency heat.
There are also a few formulas that combine peony (red or white) and moutan; for example Rhino and Rehmannia Combination (Xijiao Dihuang Tang) includes these herbs for treating bleeding due to blood heat; Cinnamon and Hoelen Formula (Guizhi Fuling Wan) includes them for treating gynecological disorders with blood stasis and blood heat.
The peony materials-red peony, white peony, and moutan-have many things in common, including bitter taste, slightly cold nature, ability to clear heat and vitalize blood, and the active constituent paeoniflorin. Some distinctions are made among the herbs, with white peony being preferred as a tonic for the yin and blood, red peony preferred for treating blood stasis and excess heat, and moutan preferred for treating deficiency heat. There is some confusion in the literature about the herbs, which appears to arise mainly from attempts to differentiate them when, in fact, they have so much in common.
Figure 2: Paeonia suffruticosa.
Figure 3: The processed roots of: baishao (top);
chishao (middle); and mudanpi (bottom).