Introduction to the Knowledge of Chinese Materia Medica

I. General Introduction

In the vast land and sea regions of China, there are rich resources of various natural drugs, which include plants, animals and minerals. More than 3,000 kinds of drugs have been recorded in various medical classics. There is a long history of development and utilization of these resources, which has been the material basis for the development of traditional Chinese medicine and pharmacology. For thousands of years, traditional Chinese drugs have been used as the main weapons in the fight against diseases and played an important role in ensuring the health of the people and the development of the nation.

Drugs of the plant origin account for the majority of Chinese drugs and are used more popularly than those of other origins; thus the study of Chinese drugs has been termed Bencaoxue (herbology) since the ancient time. A great number of medical classics and literatures, which record the Chinese people's genius inventions and discoveries in medicine and their contributions to its development, have survived the changes of times and can still be fount almost in their original forms. These classics and literatures have become an important part of the invaluable culture of the Chinese nation. The plants, animals and minerals used for medication are called Chinese materia medica because their use is based of the TCM theory, and because there is a unique theoretic system as well as special forms of application. Both their theoretic system and their special application forms fully reflect the characteristic features of the Chinese natural resources and the history and culture of China. The science of Chinese materia medica is a science that studies the basic theory of Chinese materia medica and their origin, collection, indications, effects and ways of application. It is an important integral part of TCM.

The Objects and Tasks of the Research of Chinese Materia Medica

All the substances used for treating and preventing diseases are generally called drugs. According to their origins, drugs are divided into three types: natural, chemical and biological. The natural drugs are those plants, animals and minerals found in nature which can be used for medication either directly or after being processed without major pharmacological or chemical changes. Majority of Chinese herbs, folk drugs and national drugs are natural drugs. Only very few, e.g. miniumite, are synthetics. The Chinese drug is a broad definition, which includes traditional Chinese drugs, folk drugs, herbal drugs and national drugs. Traditional Chinese drugs refer to those natural drugs or their processed products that are widely used in China and are circulated in market as merchandise. They are recorded in medical classics, and their pharmacological effects are explained with, and their clinical application is guided by, the theories of traditional Chinese medicine and Chinese materia medica. They have a unique theoretic system and special ways of application, and their processing and preparation are rather standardized. Folk drugs are those natural drugs and their processed products that are used by folk healers in the treatment and prevention of diseases. Such drugs are used mainly by experience without the guidance of a theory. Their planting, collection and preparation are done by healers themselves, and they are rarely, or not at all, recorded in medical classics. There are no standardized methods for their processing and preparation. They are used in limited regions. National drugs refer to those natural drugs used by Chinese minorities in their local regions rather than by the Han nationality. Their application is either guided by special ethnic medical theories or by experience only. In most cases they are collected and used by healers themselves. They may also be given or sold to patients by itinerant healers. The national drug is an important integral part of the traditional Chinese medical system. Its existence and development have not only enriched traditional Chinese medicine and pharmacology but also promoted the development of Chinese materia medica. Although traditional Chinese drugs, folk drugs and national drugs are different, there are close internal relations among them. Their overlapping, interpenetrating and inter-complementing have enriched and extended the concept of the Chinese drug, forming the system of Chinese materia medica in the broad sense.

Relationship between Chinese Materia Medica and Other Branches of Learning

The science of Chinese materia medica is an applied science with rich and extensive contents. It is closely related to many basic pharmaceutical subjects and other special subjects.

Chemistry---The curative effects of Chinese drugs are based on the chemical components contained in them. The study of the chemical components of Chinese drugs involves the knowledge of inorganic chemistry, organic chemistry, analytical chemistry, etc. Both the qualitative and quantitative chemical analysis are often used not only to determine whether a Chinese drug is genuine or fake and what quality it has, but also to determine the changes of the effective components of a particular medicinal plant during the research of its planting, collection, preparation and storage. Thus, inorganic chemistry, organic chemistry and analytical chemistry are among the basic courses for learning Chinese materia medica.

Herbochemistry---This is a course involving the abstract and separation of the chemical components from medicinal herbs, and the determination of their chemical structures and the relationship between the chemical structure and the pharmacological effect. This course and Chinese herbology complement each other. On one hand, the course enables one to have a deeper understanding of the chemical components contained in Chinese medicinal herbs so as to further study them. On the other hand, the study of Chinese herbology helps researchers, who are involved in the abstraction and separation of the chemical components from medicinal herbs, to have a more comprehensive knowledge of Chinese medicinal herbs, so that they can choose and determine correct raw materials for abstraction and separation and avoid unnecessary mistakes duo to the use of wrong materials.

Basic theory of TCM---This course deals with basic theories of traditional Chinese medicine, such as TCM physiology and pathology, the principles of treatment based on the differentiation of syndromes, actions of various drugs and their compatibility, and organization of prescriptions. Learning basic theories of TCM helps one to have a better understanding of the clinical application of Chinese drugs, and lays a foundation for the analysis of Chinese prescriptions and for the design of various preparations of Chinese medicinal herbs.

Pharmaceutics---The course involves the ways in which various medicinal raw materials are made into different preparations to suit clinical application. Medicinal herbs are the main raw materials used in preparation. By studying the course, pharmacists will be able to choose proper raw materials in the preparation and to decide on the proper methods and degrees for grinding and leaching.

Pharmacology---The course involves mechanisms of the actions of drugs. The study of the course will help one to have a deeper understanding of the effective components of Chinese medicinal herbs as well as their actions and clinical indications.

Botany---Most of Chinese drugs are from the plant origin. It is necessary to study botany first and to gain the knowledge about the external features, internal structures and classification systems of the plant, in order to deeply understand the origination as well as the macroscopic and microscopic differentiation features of medicinal herbs. Under the present teaching program, the contents of botany are added to the course of Chinese herbology to reduce the number of courses to be taught. This is also because the two subjects are closely related. In addition to the above subjects, basic knowledge of zoology and mineralogy will be briefly introduced later to benefit the study of the drugs of animal and mineral origins.

Classifications of Chinese Materia Medica

There are many kinds of Chinese drugs. According to the recent statistics, the total number of Chinese drugs is about 8,000; and 700 Chinese herbs or so are commonly used. Such numerous drugs have to be classified under a certain system so as to be learnt, studied and used in a convenient way. The methods of classification have been developed with human being's deepened understanding of drugs. For example, in China's first book on drugs Shen Nong Ben Cao Jing, 365 drugs commonly used at that time was classified into three groups according to their toxicity and purpose of use. Under this classification, the drugs of the first group (upper grade) were for prolonging human life and were non-poisonous. They would have no harmful effect when taken in large dose or for long time. The drugs of the second group (middle grade) were used to prevent diseases or to reinforce deficiency. Whether they were poisonous or non-poisonous would depend on how and how much they were taken. The drugs of the third group (lower grade) were for the treatment of diseases. Most of them were more or less poisonous and thus should not be used for long time. This classification is too simple and rough, and some of the drugs have been improperly classified. But at that time, it may have played a certain role in avoiding drug poisoning due to misusing. In the book Ben Cao Jing Ji Zhu by Tao Hongjing of Liang Dynasty, another 365 drugs were added to the list. In this book the drugs were divided into six groups: stones, grass, woody plants, fruit and vegetables, grains, and a group without entity. Each group is further divided into three sub-groups. This is the first time drugs have been classified according to their natural features, but the classification is still too rough. There was no important development in drug classification until Li Shizhen of Ming Dynasty compiled his famous book Ben Cao Gang Mu, in which he modified the drug classification methods used previously. In his book, drugs were divided into 16 classes, that is, water, fire, earth, stone, grass, grain, vegetable, fruit, wood, organ, worm, scale, shell, bird, beast, and human; each class was sub-divided into 60 groups according to the ecological features of the drugs. For example, the class of grass was divided into mountain grass, fragrant grass, grass on wet place, poisonous grass, creeping weed, water grass, stone grass, moss, weeds, etc. Furthermore, the plants of close genetic relationship or of the same family were arranged together. For instance, among the 53 plants of grass on wet place of class 4, 21 of them belonged to Compositae family, and 10 of them were listed in succession. This kind of classification is helpful to both the macroscopic and the microscopic identification and collection of medicinal materials, and has played an important role in clearing up the confusion about many drugs. Following are 4 classification methods used in modern textbooks on Chinese herbal medicine, each of which varies in purposes and emphases.

1. Classification according to the actions of drugs---e.g. detoxicants, heat-clearing drugs, qi-regulating drugs and drugs for activating blood circulation and clearing blood stasis, etc.

2. Classification according to medicinal parts---e.g. roots, leaves, flowers and barks, etc.

3. Classification according to effective components---e.g. drugs containing alkaloids, drugs containing volatile oils, drugs containing glycosides, etc.

4. Classification according to natural features and genetic relations---e.g. plants, animals and minerals. Plant and animal drugs are further classified and arranged according to their genetic relationship, such as Eephedraceae family, Magnoliaceae family, and Ranunculaceaer family, etc.

Each of the above classification methods has its advantages and disadvantages. Which method should be adopted mainly depends on what the purposes and requirements are. The classification according to the actions of drugs is useful for the study and research of the actions and the indications of the drugs. The classification according to medicinal parts helps to study and compare the external and internal features of various medicinal materials, thus useful for their macroscopic and microscopic identifications. The classification according to effective components benefits the study and research of the effective components of the herbal drugs as well as their chemical identification. The classification according to natural features and genetic relations is adopted because there are many similarities in the external features, internal structures, chemical components and clinical applications of the medicinal herbs of the same family. This classification method is helpful not only to the study of these similarities but also to the comparison of the differences between them. Therefore, it helps to identify each drug and to search in the same family and genus of a plant or animal drug for its substitute with the same or similar components so as to enlarge the drug resources.