History of Traditional Asian Herbal Medicine

Archaeologic evidence demonstrates that Asian herbal medicine was practiced in Asia as early as the second millennium B.C. The primary healthcare providers in Asia at that time were shamans, most of whom were women. And the primary view of disease and medicine was that disease is the manifestation of malevolent spirits, ghosts and demons that must be expelled through ritual, incantations, spells and herbal prescriptions.  The aromatic scent of herbs such as Rou Gui (cinnamon), Wu Zhu Yu (evodia) and Ai Ye (artemisia) were believed to have magical properties that affected demons or a person's spiritual powers.

Historical records of the origins of Asian herbal pharmacology are unclear.  The two most prominent nations noted to have documented the earliest use of herbal medicine are Korea and China.  Perhaps the questions of "who" and "when" are less important than those of "what" and "how" as throughout the history of the two nations, there have been repeated mergings and separations of territory, and presumably culture to a certain extent, through war, conquests, losses and more conquests of territories within the nation now known as China.  

According to Korean historical archives, edible medicine was documented as early as the Go-Chosun era (occupying the Western coast of the Yellow Sea, Southern Manchuria and Korean Peninsula between 2,333 B.C. to 238 B.C.) with the usage of herbs such as garlic and wormwood for curative purposes.  As it applies to the "what" and "how" questions, these herbs are not found in ancient Chinese pharmacology giving rise to the idea that at certain periods, each nation developed unique practices in their identification and application of herbs.  

On the other hand, the Chinese consider Yellow Emperor's Inner Classics of Medicine (Huang Di Nei Jing, 206 B.C.) compiled by various unknown authors as the foundation of traditional Chinese medicine (and Acupuncture) theory. Similarly, their archetype of Asian materia medica (herbal medicine) was a compilation of works called the Divine Husbandman's Classics of Materia Medica published around 100 A.D.  In it, the materia medica had been expanded from 28 substances noted in the Huang Di Nei Jing, to 364 substances derived from botanical, mineral and zoological sources.

By this time, medicine across Asia had evolved from a spirit view to one based on the natural order of things and on their relationships in nature which were observed to have universal validity. This philosophy of universal order is based on the complementary opposites of Yin and Yang and the Five Elements. The healing power of herbs was no longer considered to be spiritual in nature but rather inherently medicinal as their effects on symptoms were empirically observed.

Throughout the centuries the materia medica was expanded in breadth, scope and complexity as contributions from across Asia and the Middle East were propagated through trade routes. It is possible that many cultures including the Egyptians, Mesopotamians, Greco-Romans, Muslims and East Indians contributed the study, cultivation and application of their native medicinal flora and fauna to the composite of what is known today as traditional Asian herbal medicine.

At the same time traditional Asian medicine (TAM) doctors in both Korea and China developed more systematic ways to use medicinal herbs based on theoretical linkages or relationships. These relationships correlate herbal components such as energetic properties (taste and temperature); the specific organ channels entered; their specific actions on the body; their effects on specific pathogens; their energetic directional tendencies; their relationship to the Five Elements; their contraindications and incompatibilities; their interactions and potentiations; and more. Through these relationships prescription-writing came to be developed. Prescription-writing is the art and science of combining two or more herbs together to make a formula.

Today, more than 20,000 plants, minerals and zoological products have been identified throughout Asia as having medicinal properties. Of these, about a thousand are studied in the academic setting and about 300 may be commonly found in a well stocked pharmacy.

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Properties of Herbs

Properties of herbs generally refer to their nature (temperature) characteristics. Similar to the continuum theory of Yin and Yang, herbs are identified along a Cold-Hot continuum. Within the Asian materia medica, the temperature categories are:

Very Cold (Utmost Yin) Cold Slightly Cold Cool Neutral Slightly Warm Warm Hot Very Hot (Utmost Yang)

Temperature of an herb is one of the primary characteristics influencing the initial determination of its clinical use. It should be noted that temperature is not a measurable characteristic but rather, their classification evolved around the patient's reaction to the herb.

In theory, a cold-natured disorder is warmed by warming herbs. Conversely, a hot-natured disorder is cooled by cooling herbs. In the clinical setting however, cold-natured herbs may be chosen even for cold-natured disorders based on their therapeutic actions. However, the cold nature of such herbs must be balanced by including other herbs in the prescription formula that are sufficiently warming in nature.

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Tastes

In early classical texts, herbs and foods were ascribed one of the five taste characteristics based on the model of the Five Elements correspondences. The five tastes were later expanded to include other taste characteristics that do not have a direct Five Element link.

Each taste characteristic has specific effects and also partly determines the substance's therapeutic function as well as its prohibitions.

The classification of tastes and their general effects in Asian herbal medicine consist of the following:

A. Sour or Astringent

• Corresponds to Wood Element.
• Enters the Liver Channel.
• Sour is astringent and prevents the leakage of Qi and fluids.
• Sour travels in the sinews so that in diseases of the sinews, excess sour should be avoided.

B. Bitter

• Corresponds to Fire Element.
• Enters the Heart Channel.
• Bitter drains Heat and dries Dampness.
• Bitter travels in the bones so that in diseases of the bones, excess bitter should be avoided.

C. Sweet

• Corresponds to Earth Element.
• Enters the Spleen Channel.
• Sweet tonifies, harmonizes and moistens.
• Sweet travels in the flesh so that in diseases of the flesh, excess sweet should be avoided.

D. Acrid or Pungent

• Corresponds to Metal Element.
• Enters the Lung Channel.
• Pungent disperses and moves.
• Pungent travels in the Qi so that in disease of the Qi, excess pungent should be avoided.

E. Salty

• Corresponds to Water Element.
• Enters the Kidney Channel.
• Salty purges and softens hardness.
• Salty travels in the Blood so that in diseases of the Blood, excess saltiness should be avoided.

F. Bland

• Bland leaches out dampness and promotes urination.

G. Aromatic

• Aromatic is not exactly a taste but a 'temperature' characteristic.
• Aromatic describes an herb's ability to penetrate through turbidity and thickness to 'awaken' certain functions such as the sluggish digestive function of the Spleen or the dulled senses of the Mind's sensory orifices.

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Herbal Categories

Herbs are classified into functional categories based on their most important and more commonly used therapeutic function. The vast majority of the herbs can fit into multiple categories. For the sake of consistency, nomenclature and study, each herb has been traditionally placed under one of the following categories:

• Warm Herbs that Release the Exterior
• Cool Herbs that Release the Exterior
• Drain Fire
• Cool the Blood
• Clear Heat and dry Dampness
• Clear Heat and relieve Toxicity
• Clear and relieve Summerheat
• Purgatives
• Laxatives
• Harsh Expellants
• Drain Dampness
• Dispel Wind-Dampness
• Cool and transform Phlegm-Heat
• Warm and transform Phlegm-Cold
• Relieve Coughing and Wheezing
• Aromatic herbs that transform Dampness
• Relieve Food Stagnation
• Regulate the Qi
• Stop Bleeding
• Invigorate the Blood
• Warm the Interior and expel Cold
• Tonify the Qi
• Nourish the Blood
• Nourish the Yin
• Tonify the Yang
• Stabilize and Bind
• Anchor, Settle and Calm the Spirit
• Nourish the Heart and calm the Spirit
• Aromatic Substances that open the Orifices
• Extinguish Wind and stop Tremors
• Expel Parasites
• Herbs for External Application

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Channels Entered

The identification of the specific Channels 'entered' by an herb is another principal way an herb's therapeutic action is manifested. Herbs are said to enter one or more of the 12 Primary Organ Channels as a way to treat pathologies related to those Organs and Channels. It is this relationship and correlation with the Channel theory that enables the use of herbs within the theoretical framework of traditional Asian medicine. Were it not for the identification of an herb's capacity for Channel entry, clinical usage may well be limited in scope to treating discrete symptoms rather than the systemic disharmony.

In addition to channel entry by an herb, certain herbs are said to have guiding activities. This means that those herbs, when added to an herbal formula, have the capacity to focus the actions of other herbs to a particular Channel and its related Organ.

For additional information on this topic please see the section on Channels under Acupuncture.

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Contraindications and Prohibitions

Because of an herb's temperature characteristics, functional effects and, and in modern terms their biochemical behaviors, certain combinations of herbs are deemed to be antagonistic or incompatible. Consequently these combinations should be avoided less the combination should either reduce the efficacy of one or the other or produce side effects.

Contraindications are noted for many herbs. Contraindications and cautions apply to certain conditions and constitutions where use of the contraindicated herb must be done with caution. In prescription-writing, contraindicated herbs may sometimes be used with care as long as proper mitigating and harmonizing substances (herbs) are included.

In the example given below for Dang Gui, the herb is contraindicated in cases of Yin Deficiency with Heat signs. However, when necessary and as appropriate, the herb may be used in a prescription formula treating a Yin Deficiency pattern as long as herbs that nourish Yin and cool the Heat are included to mitigate the contraindication.

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Functions and Indications

As is the case for acupuncture points, herbs are also known to have multiple functions and indications. The differences between a function and indication can be explained as follows:

Function:

• A function may be thought of as a Treatment Strategy or Treatment Principle.
  
  
• A Treatment Strategy/Principle can be thought of as a summarization and general principle, or mechanism of action.
  
  
• Examples include: Clear Heat; Disperse Cold; Drain Dampness; Resolve Phlegm; Descend Rebellious Qi; Cool the Blood; Remove Obstruction; Expel Wind; Calm the Mind; Tonify and Strengthen Qi; Harmonize Blood; Nourish Yin; Supplement Yang; etc.

Indications:

• Indications refer to the discrete symptoms for which an herb is effective.
• Examples include: cough; abdominal pain; insomnia; headache; dizziness; spasms; blurred vision; skin itch; frequent urination; etc.

An example is given on the properties, functions, indications and contraindications of an important herb, Dang Gui, as presented in the book, Materia Medica, by Bensky and Gamble:

• English name: Angelica root
• Properties: Sweet, Pungent, Bitter, Warm
• Channels entered: Heart, Liver, Spleen
  
  
• Function 1: Tonifies Blood and regulates Menses.
• Indications 1: Blood Deficiency patterns with such symptoms as pallid, ashen complexion, tinnitus, blurred vision, and palpitations. Also for menstrual disorders such as irregular menstruation, amenorrhea, dysmenorrhea, etc.
  
  
• Function 2: Invigorates and harmonizes the Blood and disperses Cold.
• Indications 2: Stops pain due to Blood Stasis. For abdominal pain, trauma injury and carbuncles. Also for Blood Deficiency with chronic Wind-Damp Painful Obstruction.
  
  
• Function 3: Moistens Intestines and unblocks the Bowels.
• Indications 3: Dry Intestines due to Blood Deficiency.
  
  
• Function 4: Reduces swelling, expels pus, generates flesh, relieves pain.
• Indications 4: Treats sores and abscesses where its ability to both tonify and invigorate the blood leads to improvement.
  
  
• Contraindications: Contraindicated for Yin Deficiency with Heat signs.
• Caution: Diarrhea or abdominal distention.

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Art and Science of Prescription-writing

Prescription-writing involves combining two or more substances to make a formula for clinical use.

The science of prescription-writing requires intimate knowledge about the empirical components of herbs as briefly summarized above including their properties, categories, channels entered, contraindications, functions and indications, as well as aspects not discussed including their interactions, dosages, preparation, storage, and more.

To aid the practitioner in the selection of herbs, classical texts have provided various theories and guidelines on herbal combination. One of the more popular guidelines emphasizes the following features to consider in combining or avoidance of combining certain substances:

• Mutual Accentuation: combining based on similar functions to accentuate their therapeutic actions.
• Mutual Enhancement: combining substances with different actions to enhance the effect of the primary herb.
• Mutual Counteraction and Suppression: combining of substances that will reduce a substance's toxicity or side effects.
• Mutual Antagonism: combining based on the ability of two substances to minimize or suppress an herb's positive actions.
• Mutual Opposition: combining of substances that would produce side effects or toxicity.

The Artistry of prescription-writing is, like the art of acupuncture points combination, more elusive. Artistry applies to the way a practitioner selects a particular group of herbs, among those having similar properties and behavior, that will not only produce a desired effect, but do so in a way that will address the patient's underlying condition in an harmonious way. Harmony is the balanced end result of the prescription's overall effect on the patient. To arrive at harmony requires, to some degree, a judgment call regarding the particular herbs selected.

As it was written about the artistry of acupuncture points selection, artistry of Asian pharmacology begins with knowledge. Knowledge then is flavored by one's creativity. And creativity must evolve through failures and mature through successes.