(1) A Brief History of the Development of
(2) The Development of Modern TCD
(3) The Sources of TCD
(4) Processing of TCD
(5) The Properties and Actions of TCD
(6) Meridian Classification (Guijing) of TCD
(7) Toxicity of TCD
(8) Compatibility and Incompatibility of Drugs in a
(9) Decoction of TCD
(10) Method and Time of Administration of
Traditional Chinese pharmacology, pharmacology in the broad
sense, is an important integral part of traditional Chinese
medicine (TCM). It deals with the origin, collection, processing,
actions and uses of traditional Chinese drugs (TCD), or Chinese
materia medica, under the guidance of the basic theory of TCM.
There are very rich resources of TCD. According to a recent
survey, the number of TCD is 12,807. Among them, 11,146 are drugs
of plant origin; the rest are of animal or mineral origin. Hence,
traditional Chinese pharmacology is sometimes called traditional
Chinese herbal pharmacology.
Beginning in the 1920s, modern Chinese pharmacologists started
to study the actions of TCD in terms of modern medical science.
Since the 1950s, there has been an increasing number of Chinese
pharmacologists and related scientists engaged in the study of TCD.
Chemical ingredients and fractions have been isolated from a large
number of TCD, and their actions have been studied.
(1) A Brief History of the
Development of TCD
In ancient times, people came to realize that some plants and
animal parts had dramatic effects when consumed by humans, such as
causing vomiting, perspiration, diarrhea, etc. There was a legend
that 4,000 years ago there was an emperor called Shen Nong (shen
means god; nong means agriculture), who devoted himself to the
development of agriculture. He tasted hundreds of plants to find
out if they were fit to eat, in the process discovered many plants
with pharmacological effects. Hence, the name of the first
classical work on Chinese materia medica, published around 1,800
years ago, was attributed to him, and known as Shen Nong’s Herbal
Classic (Shen Nong Ben Cao Jing). It contains details of 365
Various methods of processing of these natural drugs were
developed and summarized in a book named Lei’s Treatise on the
Preparation of Drugs (Lei Gong Pao Zhi Lun), written by Lei Xiao
around 1,500 years ago. It was the first book of its kind. After
processing, either the effectiveness of the processed drug
increased or its toxicity decreased.
The number of TCD increased steadily as the years went by. In
the Tang Dynasty (618-907), for the first time the government
published (in 659) a book on TCD named The Newly Revised Materia
Medica (Xin Xiu Ben Cao) or The Tang Materia Medica (Tang Ben Cao),
which included details of 850 drugs, many of them were illustrated.
Fifty years later, a book named Dietetic Materia Medica (Shi Liao
Lei Ben Cao), written by Dr Meng Xian on drugs used as food, was
published. In the Song Dynasty (960-1279), Dr Tang Shenwei edited
Classic Classified Materia Medica for Emergencies (Jing Shi Zheng
Lei Bei Ji Ben Cao), or the Classified Materia Medica (Zheng Lei
Ben Cao), which listed 1,746 drugs and had many useful
prescriptions attached. In the Ming Dynasty (1368-1644), a
monumental work on materia medica, Compendium of Materia Medica
(Ben Cao Gang Mu), was compiled by the great doctor and pharmacist
Li Shizhen and published in 1590. In 52 volumes, it contained
details of 1,892 drugs, 1,160 pictures and 11,096 prescriptions.
This was a multidisciplinary book of botany, pharmacognosy,
pharmacology and therapeutics. The Chinese Materia Medica
Dictionary, published in 1977, contained details of 5,766 drugs,
while the Glossary of Chinese Materia Medica, published in 1993,
contained details of 8,488 drugs. A recent survey found that the
number of TCD has now been raised to 12,807, among which 11,146 are
drugs of plant origin, 1,581 are drugs of animal origin, and 80 are
(2) The Development of Modern TCD
The modern pharmacology of TCD started in China 70 years ago,
when Dr KK Chen (Chen Kehui) published a paper on ephedrine. There
were around 30 TCD studied from the 1920s to the 1940s by
phytochemists and pharmacologists, such as danggui (Radix Angelicae
Sinensis), huanglian (Rhizoma Coptidis), chuanwu (Radix Aconiti),
changshan (Radix Dichroae), fangji (Radix Stephaniae Tetrandrae),
beimu (Bulbus Fritillariae), yanhusuo (Rhizoma Corydalis), etc.
Beginning in the 1950s, the government has paid great attention
to the development of TCM. TCM colleges have been established in
every province and autonomous region, and TCM hospitals and
research institutes at the national, provincial, municipal and even
county level have been set up. The development of TCM has thus
entered a new era.
The trend of development of TCD is in two directions: One treats
TCD as ordinary natural resources, plants and/or animals, and
endeavors to extract new chemical ingredients from them. A number
of compounds have been isolated and identified. Their actions have
been studied and they have undergone clinical trials. Hence, a
number of new drugs have been developed and marketed, such as
tetrandrine, tetramethylpyrazine, artemisinine and its derivatives,
ferric acid, etc.
The other is the study of TCD under the guidance of TCM theory,
mainly studying the actions of prescriptions experimentally and
clinically. The traditional pharmaceutical preparations are also
undergoing transformation. New forms of patent TCD are instant
powders, tablets, injections and capsules. In order to elucidate
the actions of prescriptions, both classical and contemporary,
actions of drugs in the prescription individually and in
combination have been studied and clarified. Chemical constituents
in prescriptions are also being investigated. Hence there is both a
need and the conditions to form a modern pharmacology of TCD which
will include both the classical descriptions of actions and uses in
TCM and the new information and data obtained from the study of TCD
using modern technology and expertise. As a result, since the
1980s, the pharmacology of Chinese materia medica has been listed
as a course in the curriculum of colleges of TCM, and textbooks
have been published. Yet, TCM pharmacology is still at the infant
stage, and there is still a lot of work to be done.
(3) The Sources of
TCD consist of natural substances, such as plants, whole or
parts of animals, and minerals. As stated above, drugs of plant
origin are the main part of TCD. Their species, habitat, collection
and storage are important factors determining their quality and
3.1 Varieties of TCD
Some TCD occur in a number of varieties. This is due to the
similarity of appearance of different plants grown in different
places. Ancient doctors in different places used local types. But,
in fact, the varieties sometimes are not of the same potency, due
to the difference in the content of active principles. Some of them
even have no effect. Hence, in clinical use as well as in
experimental study, identification of the authentic family and
species of the drug is of great importance.
3.2 Habitat of TCD
Most of the TCD are of plant origin. The quality of the soil in
different places may not be the same, and so the content of active
principles may not be the same in drugs of same family and species
grown in different places. The quality of water and the local
climate (hours of sunshine, rainfall, etc.) are also influencing
factors. Thus, in ancient times there were so-called “genuine”
drugs, which meant drugs of the right species, grown at the place
where the drug is of the highest potency and the first one of the
kind used. Nowadays, many TCD, both of plant and animal origin, are
artificially grown in order to meet the increasing needs. Their
quality has been studied and controlled.
3.3 Collection of TCD
The quality of drugs is closely related to the time, season and
method of collection. The amount and quality of active ingredients
in drugs of plant or animal origin vary greatly in the course of
growth. The TCM classic called Supplement to the Essential
Prescriptions Worth a Thousand Pieces of Gold states that if a drug
is not collected at the right time it may be as worthless as a
piece of rotten wood.
In general, a drug consisting of leaves or an entire herbaceous
plant should be collected when its flowers are in full boom. For
example, the total alkaloid content in Herba Leonuri when its
flowers are in full bloom is 1.26 percent, while it is 0.39 percent
when its fruits are ripe. Most drugs from flowers should be
collected when the flowers are blooming. But some of them should be
collected when the flowers are still in bud. For example, the
content of rutin in the flowers of the Chinese scholartree is 13
percent, while in the buds it is 23.5 percent. Drugs from fruits
are usually collected when the fruits are ripe. But some such drugs
should be collected when the fruits are immature, for example,
immature bitter orange and Tibet Fructus Canarii. Drugs from roots
or rhizomes should be collected in late autumn or spring. Drugs
from bark should be collected in spring or early summer.
(4) Processing of
As TCD are drugs of plant, animal or mineral origin, they are
natural products, and should be processed before being taken as
4.1 The purpose of processing:
4.1.1 To increase potency, and hence effectiveness
For example, honey is used to process Flos Farfarae, to increase
the effect of moistening the lungs to arrest coughing. Herba
Epimedii is fried with sheep fat to increase its action of
replenishing the kidneys for treatment of impotency. Rhizoma
Corydalis is fried with vinegar to increase the solubility of its
alkaloids and raise its analgesic effect.
4.1.2 To alleviate potency, or minimize or eliminate side
effects or toxicity
Aconitine is the toxic ingredient of Radix Aconiti, which often
causes arrhythmia. When Radix Aconiti is boiled or steamed with
licorice and black beans, the content of aconitine is lowered. The
toxicity is thereby reduced. The strong purgative action of Semen
Crotonis or Semen Euphorbiae Larhyridis can be attenuated by
removing their oil content and making them into a frostlike powder
4.1.3 To change the action or site of action of drugs
Through processing, the action or site of action may be changed to
a varied extent. For example, after processing, the purgative
action of dahung (Radix et Rhizoma Rhei) can be attenuated and the
action of clearing away heat and detoxification can be enforced.
The action of caihu or xiangfu (Radix Bupleuri or Rhizoma Cyperi)
can be concentrated more on the liver after being processed with
4.1.4 To make the drugs easier to prepare or store
Drugs such as seeds or shells, and drugs of mineral origin should
be ground or processed to make them easy to prepare or to make
their active principal easy to dissolve. Drugs of plant origin
should be heated or dried in order to inactivate the enzymes
contained in them, to make them easy to store for a longer
4.1.5 To clear away unwanted substances such as grit, unpleasant
4.2 Methods of processing
4.2.1 Physical processing
Picking out impurities, winnowing, scraping and brushing.
4.2.2 Liquid processing
Soften the drugs by moistening them with small amount of liquid,
such as water, wine, ginger juice, etc.
Place the drugs in running water or frequently changed water to
remove unpleasant odors, salt or toxic components.
Refining powder with water
This method is used usually to process mineral drugs. The mineral
drug is ground into fine powder together with water, and stirred in
the water. The fine powder will be suspended in the water. The
suspension will be precipitated and the precipitate is then dried
to get fine powdered drugs for use.
4.2.3 Fire processing
There are different degrees of baking: carbonizing, and baking to a
yellowish or brown color. Baking to a yellowish or brown color will
facilitate the dissolution of active ingredients. Carbonizing will
attenuate toxicity and potentiate an astringent action. Sometimes
drugs are baked with soil, bran or rice to increase their
therapeutic action and reduce irritation.
Stir-baking with adjuvant
The drug is baked mixed with fluid adjuvants such as wine, honey,
vinegar, salt water, etc. to increase their therapeutic effect or
reduce adverse effects.
There are two ways of calcining: one is to use strong fire to
calcine the drug directly. This is used usually in the case of
mineral and shell drugs. The other way is to put the drug in a
covered refractory vessel and heat till the drug becomes
“Wei” (roasting in hot ashes)
“Wei means to wrap a drug in wet paper or wet wheat powder, and
place it in hot ashes till the paper or wheat powder is charred.
The drug itself is not charred and its toxicity or intensity is
4.2.4 Processing by both water and fire
The drug is boiled in water or another liquid such as vinegar or
wine to reduce side effects or to increase potency.
The drug is steamed in water or wine steam to attenuate side
effects or to increase potency.
This method is applied to mineral or shell drugs. The drug is made
red-hot, and then put into water or some other liquid such as
vinegar or wine to make it light and crisp. The drug becomes easy
to make into a pharmaceutical preparation.
The drug is placed in boiling water for a very short time. This
makes it easy to dry.
These include germination of paddy rice, wheat or barley;
fermentation of a combination of drugs and wheat powder; frost-like
(5) The Properties and Actions of
5.1 The four properties
These are cool, cold, warm and hot. In TCM, diseases are
classified into two major categories, that is, cold and hot. Drugs
that can treat cold diseases are assigned warm or hot properties;
drugs that can treat hot diseases are considered to have cool or
cold properties. Cool or cold, and warm or hot are just a matter of
difference in strength. Cool is weaker than cold, and warm is not
as strong as hot. Drugs with cool or cold properties usually have
such actions as “clearing away heat and toxic materials”, “removing
heat from blood”, “nourishing yin” and “purging fire”. In addition,
drugs with warm or hot properties can warm the interior, dispel
cold, support yang and replenish qi. In terms of yin and yang, cool
and cold belong to yin, and warm and hot belong to yang.
Clinical studies of body temperature, heart rate, blood
pressure, respiratory rate, and amount of saliva secreted have
shown that most patients with hot diseases show a hyper-reaction of
the sympathetic nervous and adrenergic system, while patients with
cold diseases usually show a hypo-reaction of this system. When
patients with hot diseases are treated with cold drugs, not only
are their feverish symptoms relieved, but there is a decrease in
the heart rate, amount of catecholamines and 17-hyroxycorticoids
excreted in the urine. The very opposite occurs when patients with
cold diseases are treated with hot drugs. These effects of cold and
hot drugs have also been verified by experiments.
Experiments have also shown that warm and hot drugs can increase
the oxygen consumption of rat tissues, carbohydrate metabolism and
amount of water taken. They can postpone the onset of death in a
cold environment and slow the decrease of body temperature. Cool
and cold drugs have the opposite effects. There is evidence that
warm and hot drugs can promote the metabolic process, while cool
and cold drugs can inhibit it.
It has been found that cold drugs usually have tranquilizing,
sedative, analgesic or anti-convulsant actions, while warm drugs
usually stimulate the central nervous system.
Cold drugs usually have anti-microbial, anti-inflammatory and
anti-toxin actions. Some even have anti-tumor actions.
5.2 The five tastes
Traditionally, TCD have been regarded as having five kinds of
tastes, i.e. pungent, sweet, sour, bitter and salty, although some
drugs may be stringent or tasteless. Nonetheless, the five tastes
are standard. Clinical practice has found that each kind of taste
is closely related to the relevant drug’s therapeutic
5.2.1 Pungent taste
A pungent taste is usually due to the content of volatile oils in a
drug. Such drugs have the function of expelling exopathogens from
the superficies of the body mainly by means of perspiration.
Pungent drugs have an activating or pushing action to promote
the flow of qi and the circulation of blood.
Pungent drugs possess the action of moistening tissues, because
they can promote the circulation of blood.
Pungent drugs can cause dryness, which leads to exhaustion of qi
and yin, due to their dispersing action. Hence, they should be used
with care to treat patients with deficiency of qi and yin or
deficiency in the exterior with hyperhydrosis (excessive
5.2.2 Sweet taste
Drugs of this kind usually contain amino acids and saccharides.
They are mostly drugs with tonifying effects. For example,
ginseng and Astragalus (huangqi), with sweet and warm properties,
are qi tonics, and Radix Glehnia (bei shashen) and Radix
Ophiopogonis (maidong), with sweet and cold properties, replenish
Drugs such as licorice and honey, with a sweet taste, can
regulate the actions of drugs combining together or relieving
spasms and pain.
Some sweet drugs can moisten the lungs to resolve phlegm, and
moisten the intestines to relieve constipation.
5.2.3 Sour taste
Drugs with a sour taste usually contain organic acids and tannins.
Drugs of this kind can arrest sweating, spontaneous emission or
leukorrhagia, astringe qi, stop bleeding or relieve diarrhea. Some
sour drugs can stimulate the appetite and promote digestion.
5.2.4 Bitter taste
Drugs with a bitter taste usually contain alkaloids and glycosides.
They can cause purgation, check the upward flow of qi and clear
away fire. Bitter drugs with cold and warm properties can eliminate
warm and cold dampness, respectively. In addition, a small amount
of a bitter drug can stimulate the appetite and promote
5.2.5 Salty taste
A salty taste is mainly due to the content of inorganic salts.
Drugs such as Natrii Sulphas and sodium sulfate can act as
purgatives and soften hard masses, and drugs such as Concha Ostreae
can resolve scrofula and subcutaneous nodules.
5.2.6 Astringent taste
There is a small group of drugs with astringent taste. They have a
similar action to sour-tasting drugs. They are used to treat
sweating due to debility, diarrhea, bleeding, frequent micturition,
5.2.7 Tasteless drugs
A small number of drugs have no special taste. They can remove
dampness and promote diuresis.
In TCD, every drug has both property and taste. Hence, in
clinical use the property and taste of a drug should be considered
together in treating diseases.
5.3 Ascending and descending, floating and sinking
These are peculiar properties of drugs stated in TCM to show the
inclination and direction of their action. Ascending and floating
indicate that the action of the particular drug is going upward or
outward within the body, while descending and sinking imply going
downward and inward. These activities will counteract pathologic
actions which are going in the opposite directions.
The drugs with ascending and floating actions are drugs
elevating the yang, dispelling pathogenic factors from the exterior
of the body, expelling coldness and causing vomiting. Drugs with
descending and sinking actions are drugs with the properties of
clearing away heat, catharsis, inducing diuresis, checking
perverted flow of qi and relieving asthma.
The properties of ascending and descending, floating and sinking
are closely related to the properties and tastes, processing and
compatibility of drugs in a prescription. For example, most
ascending and floating drugs have pungent or sweet tastes and warm
or hot properties, while descending and sinking drugs have sour,
bitter or salty tastes and cool or cold properties. Drugs processed
with alcohol will become lifting; with salt will become laxative;
with ginger will become dispersing; and with vinegar will become
astringent. Dahuang (Radix et Rhizoma Rhei) has a bitter taste and
cold property, which is descending, and is used to treat
constipation. But if it is processed with liquor, dahuang will
clear away heat and toxic materials, and can be used as an
antibiotic and antipyretic agent. The action of drugs can be
modified by combination with other drugs. For example, chenpi
(Pericarpium Citri Reticulatae, tangerine peel) acts as a tonic if
used in combination with tonic drugs, as a purgative when combined
with purgatives, and will be ascending when combined with ascending
drugs and descending when combined with descending drugs. Some
drugs act as agents to float other drugs upward, e.g., jiegeng
(Radix Platycodi, ballonflower); while niuxi (Radix Achyranthis
Bidentatae) can make other drugs sink.
(6) Meridian Classification (Guijing)
The classification of TCD according to meridians, or guijing,
means that each drug has a selective action manifested on one or
several specific meridians. In TCM, meridians are closely connected
with the internal organs (zang and fu). Hence, drugs are grouped or
classified, for instance, as drugs of Lung Meridian of Hand Taiyang
(LU), Stomach Meridian of Foot Yangming (ST), etc. This
classification is helpful for choosing drugs to treat disorders of
According to studies of pharmacological actions using modern
pharmacological methods, the guijing of a particular drug is
manifested in line with its pharmacological actions. For example,
in TCM the organ gan (liver) is considered as “determining the
conditions of tendon” and “endogenous wind marked by vertigo,
spasms and convulsions are related to gan.” There are 22 drugs
having anti-spasm and anti-convulsive actions, classified as
belonging to the Liver Meridian of Foot Jueyin (LR). In TCM, the
large intestine is considered an organ for passing wastes. There
are a number of drugs classified as belonging to the Large
Intestine Meridian of Hand Yangming (LI), having a purgative
action. Fei (lungs) is an organ in charge of qi, performing the
function of respiration and storing sputum. Drugs classified as
belonging to the Lung Meridian of Hand Taiyin (LU) have
antitussive, expectorant and antiasthmatic actions. Therefore,
guijing really means the site of action of drugs on particular
(7) Toxicity of TCD
In terms of toxicity, TCD can be classified as non-toxic,
slightly toxic, moderately toxic and extremely toxic. In the
ancient literature of TCD, it is stated that no drugs is non-toxic
if it is taken in excessive doses or over too long a period of
In short, when TCD are used to treat disease, all the
properties, actions, tastes and toxicity should be considered at
the same time. Then TCD are chosen according to the zheng (syndrome
(8) Compatibility and Incompatibility
of Drugs in a Prescription
In clinical practice, traditional Chinese medical doctors
usually prescribe around ten or more TCD to make a formulation,
based on overall analysis of patients’ symptoms and signs (zheng).
It is important to determine whether or not the drugs in the
formulation are compatible with each other and how they interact
with each other.
8.1 First of all, there are four categories of drugs in a
prescription, namely, the principal, adjuvant, auxiliary and
conductant drugs. The principal drug(s) provides the principal
curative action. The adjuvant drug(s) strengthens the action of the
principal drug(s) and treats the secondary symptoms. The auxiliary
or correctant drug(s) is used to relieve minor or secondary
symptoms or to temper the action of principal drug(s) when the
latter is too potent. The conductant drug(s) directs the action to
the affected meridian or site.
Drugs in a prescription interact with each other in the
following six ways: (1) mutual reinforcement: two drugs having
similar properties and actions reinforce each other; (2)
assistance: two more drugs in a prescription with one as the
principal drug and the rest playing an adjuvant role; (3) mutual
restraint: different drugs weaken or neutralize each others’
actions; (4) neutralization: one drug neutralizes the side effects
of another drug; (5) counteraction: one drug antagonizes the
therapeutic action of another drug; and (6) incompatibility: two
drugs put together will result in enhanced side effects or
8.2 Based on the interactions of drugs in a prescription, some
incompatibilities occur when combining drugs. There are the
so-called 18 incompatible medicaments and 19 medicaments of mutual
restraint. The 18 incompatible medicaments are as follows: Radix
Glycyrrhizae (gancao) is incompatible with Radix Euphorbiae
Pekinensis (daji), Flos Genkwa (yuanhua), Radix Euphobiae Kansui
(gansui) and Sargassum (haizao); Radix Aconiti (fuzi) is
incompatible with Bulbus Fritillariae (beimu), Fructus
Trichosanthis (gualou), Rhizoma Pinelliae (banxia), Radix
Ampelopsis (bailian) and Rhizoma Bletillae (baiji); Radix Veratri
Nigri (lilu) is incompatible with Radix Ginseng, Radix Salviae
Miltiorrhizae (danshen), Radix Adenophorae and Radix Glehniae (nan
shashen and bei shashen), Radix Sophorae Flavescentis (kushen),
Radix Scrophulariae (xuanshen), Herba Asari (xixin) and Radix
Paeoniae (shaoyao). If the above-listed drugs are put together in a
formulation, it is said that there will be serious side effects.
The 19 medicaments of mutual restraint are as follows: Sulphur
restrains crude sodium sulfate; mercury restrains arsenic trioxide;
Radix Euphorbiae Ebracteolatae (langdu) restrains litharge; Semen
Crotonis (badou) restrains Semen Pharbitidis (qiannuzi); Flos
Caryophylli (dingxiang) restrains Radix Curcumae (yujin);
crystallized mirabilite restrains Rhizoma Sparganii (sanleng);
Radix Aconiti (chuanwu) and Radix Aconiti Kuznezoffii (caowu)
restrain Cornu Rhinoceri (xijiao); Radix ginseng restrains Faeces
Trogopterorum (wulingzhi) and Cortex Cinnamomi (guangui) restrains
Halloysitum Rubrum (chishizhi). These drugs, when put together,
will restrain or neutralize each other’s actions. Modern
pharmacological studies on the 18 incompatible medicaments and 19
medicaments of mutual restraint have not yet elucidated the
mechanism of these actions.
8.3 Contra-indication during pregnancy
Some drugs used during pregnancy may endanger the fetus, causing
abortion even miscarriage. Drugs that are prohibited or should be
used with great caution during pregnancy are those that have a
drastic action or are very toxic, such as Semen Crotonis (badou),
Hirudo (leech, shuizhi), Tabanus (gadfly, mengchong), Radix
Euphorbiae Pekiensis (daji), Flos Genkwa (yuanhua), musk, Rhizoma
Sparganii (sanleng), Rhizoma Curcumae Zedoariae (ezhu) and mylabris
(Chinese blistering beetle, banmao). Drugs that should be used with
great caution are those with drastic actions of relieving qi
stagnation and removing blood stasis, or are highly pungent, very
warm, highly lubricating or purgative, such as Fructus Aurantii
Immaturus (zhishi), Semen Aracae (binglang), Semen Persicae
(taoren), Radix Aconiti Lateralis Praeparata (fuzi) and Rhizoma
8.4 Dietetic restraint (food taboo)
During treatment with herbal drugs, some types of food that are
unsuitable for the condition of the patient or are
contra-indicative to some drugs should be avoided or their intake
limited. Uncooked or cold food is unsuitable in cases of cold
syndrome; and hot, pungent or greasy food is unsuitable in case of
warm syndrome. In take of pepper, chillies, alcoholic beverages,
garlic, etc. should be limited in cases of dizziness, insomnia and
agitation. For patients with indigestion due to deficiency of the
spleen and stomach, fried, greasy and sticky foods should be
avoided. Patients with suppurative infection on the skin and
pruritus should not take fish, shrimp, crab or other seafood or
irritating foods. In addition, there are records in the ancient
literature that Radix Dichroae (changshan) is incompatible with
Bulbus Allii Fistuloi (Chinese green onion, scallion, cong); Radix
Rehmanniae and Radix Polygoni Multiflori (heshouwu) are
contra-indicated for Chinese green onion, garlic and radish.
Peppermint counteracts turtle flesh; Porai is not compatible with
vinegar; Corapax Trionycis (turtle shell) is antagonistic to
Amaranthus tricolor (xian); honey to scallions, and so on.
8.5 Dosage of drugs
Dosage is determined by the following factors:
8.5.1 Properties of drugs
In general, drastic and toxic drugs should be given in small
doses at the beginning, and the doses should be increased
gradually. However, drugs of less-potency or great density (such as
mineral and shell drugs) should be given in larger doses.
8.5.2 Compatibility and form of preparation
Since there are principal, adjuvant, auxiliary and conductant
drugs in a prescription, the dosage of the principal drug(s) is
usually larger than that of the others. As to the form of
preparation, the dosage of drugs in a decoction is larger than that
in bolus or powder forms.
8.5.3 Condition of the disease, and constitution and age of the
The dosage given in the case of serious, emergency and stubborn
conditions should be, in general, larger. For mild and chronic
diseases, the dosage may be smaller. Strong patients can take
larger doses, while aged or weak persons, children should take
smaller doses. The dosage for a child over six years old should be
half of that for an adult. The dosage for a child under five should
be a quarter of that for an adult, and for an infant even
8.5.4 Geographic features
The temperature in the southern areas of China is high, hence
the dosage of diaphoretics (drugs for treating exterior syndromes)
should be small. As the temperature in the northern parts of China
is lower, the dosage should be larger. In the summer, humidity is
high, and so the dosage of drugs with fragrant odors to resolve
dampness should be larger, while the dosage of diaphoretics and
drugs for warming yang should be smaller. In winter, drugs for
warming yang and diaphoretics may be given in larger doses.
(9) Decoction of TCD
9.1 The conventional way of preparing TCD for administering to
patients is to decoct or boil the drugs. TCD should be boiled in a
vessel with stable chemical properties, such as an earthenware or
enamel pot. Clean water is then poured in and over the surface of
the drug(s). The drug(s) is then immersed for about 60 minutes,
then boiled with high heat and then gentle heat for 20-40 minutes,
depending on the property of the drug(s). Later, the supernatant is
taken out. Water is poured in again, the drug(s) is boiled once
again. Usually two or three supernatants are poured in together,
and divided into two portions to be given to patients.
9.2 Some drugs should be decocted first, such as some drugs of
mineral and shell origin, namely Gypsum Fibrosum (gypsum, shigao),
Concha Ostreae (oyster shell, muli), Concha Haliotidis (sea-ear
shell, shijueming), Plastron Testudinis (tortoise plastron,
guiban), etc. Because such drugs are firm and hard, their active
ingredients are difficult to boil out. They should be boiled 15
minutes before other drugs are boiled.
9.3 Some drugs should be boiled later than other drugs, such as
aromatic drugs of which the active ingredients are easy to
evaporate or decompose. So, they should be put into the decoction
after other drugs have been boiled for 5-15 minutes. Then the
decoction is boiled for another five minutes. Such drugs include
Herba Menthae (field mint, bohe), Fructus Amomi (spiny amomum
fruit, sharen) and Radix et Rhizoma Rhei (rhubarb, dahuang).
9.4 Some drugs should be wrapped before decoction. This is
important for drugs that are powdered, downy or mucilaginous, such
as Flos Inulae (xuanfuhua), Semen Plantaginis (cheqianzi), etc.
9.5 Some drugs should be decocted separately. This is important
for certain valuable drugs which are usually administered in small
amounts, such as ginseng, American ginseng, rhinoceros horn, etc.
After decoction, the drugs may be administered separately or mixed
with other decocted drugs.
9.6 Some drugs should be taken after powdering and pouring water
on them and stirring the solution or suspension. This is important
for drugs that are not suitable for boiling, such as amber, Radix
Notoginseng (sanqi), etc., and for some liquid drugs such as bamboo
juice, fresh ginger juice, etc.
9.7 Some drugs should be dissolved in water or melted before
being taken. Drugs such as malt extract or ass-hide glue are in
(10) Method and Time of
Administration of TCD
For decoctions, one dose per day is usually enough. The
decoction may be divided into two or three portions, to be taken
two or three times a day. For serious or acute conditions, a
decoction should be taken every four hours until the patient’s
condition improves. Tonic drugs should be taken before meals.
Patients with cold syndrome should take warm decoctions, and vice
versa. If TCD are in pill or tablet form, they can be taken orally
with warm water. The dosage will be specified by the physician.
In short, the modern science of Chinese materia medica
encompasses a series of disciplines, such as pharmacognosy,
phytochemistry, pharmacology and formulations of TCD, processing of
TCD, pharmaceutics, clinical pharmacology of TCD, etc. Meanwhile,
there are still many aspects of TCD which modern technology can
shed further light on.
(Source: The Essentials of Traditional Chinese Herbal
Medicine, Foreign Language Press, 2001)