Ancient Chinese Pharmacology
Chinese pharmacology, created by generations of physicians through their experiences, is an important branch of traditional Chinese medicine.
History
There is a legend that tells of an emperor, Shen Nong, tasting herbs in his quest for medicines. The reign of that emperor, believed to be a specific period in the New Stone Age, saw the beginnings of primitive farming. People began to study and understand the properties of crops and other plants and came to know the pharmacological functions of some of them. The "tasting" of herbs by that legendary emperor should be taken as an ancient version of the story of research workers personally investigating the therapeutic effects of herbal medicines. A number of herbs, Asiatic plantain, fritillary, motherwort and others, are mentioned in Shi Jing (Book of Songs). Shan Hai Jing (Classic of Mountains and Rivers) written over 2,000 years ago named a total of 120 drugs of vegetable, animal and mineral origin and described their effects in treating and preventing diseases as well as their processing and administration. Though further archaeological research has yet to be done to identify many of the drugs named, such ancient works revealed the progress of pharmacological studies at that time.
Around the 2nd century B.C. Shen Nong Ben Cao Jing (Shen Nong's Materia Medica) appeared as China's earliest pharmacological work. It dealt with 365 drugs divided into three categories. This Materia Medica discussed at length the geographical origin, properties, collection and therapeutic value of each medicinal herb. It also told how to prescribe, administer and process each. Special mention should be made of the fact that the ancient Chinese found through long clinical experience specific medicines for certain diseases, such as ephedra for cough and asthma, rhubarb as a purgative and dichroa root for malaria. The effectiveness of these specific medicines has been confirmed by modern pharmacologists.
By the 6th century, however, Shen Nong's Materia Medical had fallen behind clinical needs. To fill this gap, the renowned physician of that time, Tao Hongjing, comprehensively reviewed all the known drugs, relying on the empirical knowledge so far gained. He produced his Ben Cao Jing Ji Zhu (Commentaries on Materia Medica) in which he described 730 medicines, or twice the number dealt with in the original work. He also improved on the classification system of the drugs, dividing them into seven groups: herbs, arboreal plants, cereals, animal products, minerals, garden products and those with unidentified effects. His classification, which went far beyond that of his predecessors who considered only the toxicity of the drugs, was the standard for physicians and research workers during the following 10 centuries. Tao also pioneered in listing the drugs according to their respective therapeutic action, placing medicines that relieve rheumatic pains and colds as fangfeng (Sapo-shnikovia divaricata), large-leaved gentian, fangji (Stephania tetrandra) and duhuo (Angelica grosseserrata) in one category. Such classification better suited therapeutic needs and facilitated the advance of medical science and pharmacology.
The Tang Dynasty (618-907) was the golden period of Chinese feudal society, with feudal culture developing tremendously. A pharmacological compilation sponsored by the imperial court was published in A.D. 659. It listed 8.44 medicines in nine categories with illustrations based on specimens collected in different parts of China. This great work, Xin Xiu Ben Cao. (Revised Materia Medica), summed up the pharmacological knowledge accumulated through more than 10 centuries and was China's first pharmacopoeia. Its publication stimulated the later development of pharmacological science by standardizing the nomenclature of the medicines and revising their descriptions.
The 16th century saw an unprecedented upsurge in Chinese pharmacology. Capitalism in embryo had already emerged in the national economy. Transactions with foreign countries were facilitated by improved means of transportation and development in mining, and the science of farming made it both necessary and possible to sum up a new pharmaceutical knowledge. The celebrated naturalist Li Shizhen (1518-1593) was the one to fulfil this task. Through long clinical practice and learning from the common people, Li completed his Ben Cao Gang Mu (Compendium of Materia Medica), a masterpiece known the world over. Completed in 1578, the 52-volume encyclopaedia contained not only descriptions of 1,892 medicines with illustrations but also 11,000 prescriptions in 16 different parts. It reviewed the discourses by earlier pharmacologists, making corrections in them, and gave serious materialistic refutation to the Taoist alchemists who preached the attainment of immortality by means of magic pills. This voluminous work touching upon many branches of natural science, including zoology, botany, chemistry, mineralogy, geology, agronomy, astronomy, geography, etc., gave strong stimulus to later generations. Having been translated, wholly or partly, into Japanese, English, German, French, Latin, Russian and some other languages, it enjoys recognition by medical men of many countries. It has been confirmed that when the English scientist Charles Darwin quoted from what he called "the ancient Chinese encyclopaedia" he referred chiefly to this great work. Its author, Li Shizhen, was indeed a brilliant world scientist of his time.
We have so far dealt with only a few typical works in the extensive treasure of ancient Chinese literature of Materia Medica, but even these suffice to reveal the long history and world significance of Chinese pharmacology.
Unique Content
Chinese pharmacology is unique in its theory. As an independent system, the theory is based on the knowledge of the diseases and of the natural properties and therapeutic effects of the medicines. Medicines are classified according to their "temperature" (cold, cool, warm and hot) and "tastes" (hot, bitter, salty, sour and sweet) as well as their nature of being "ascending" or "descending". The "cold" or "cool" medicines are for fevers, the "hot" or "warm" type to be applied in diseases with the symptom of weakness or low temperature, especially cold extremities. A medicine is referred to as "ascending" if it induces perspiration (like ephedra) or relieves the feeling of pressure at the rectum (like dahurian bugbane). Such herbs as lily magnolia and perilla whose flowers or leaves are used as medicine are generally "ascending" in the direction of their action, while seeds like those of trifoliate orange or minerals like red ochre are mostly "descending". Modern experiments and analysis show that such classifications are, founded on clinical experience. The "bitter" and "cold" medicines coptis and the root of large-flowered skullcap, for example, have been confirmed as containing bacteriocidal and bacteriostatic substances and are thus antipyretic. And betelnut palm, a medicine often administered as a vermicide, is found to contain arecain which is an effective paralyser of parasites, especially tapeworms.
Chinese pharmacology is unique also in the process of preparing the medicines. There are the techniques of fluid treatment, heat treatment and fluid-heat treatment. Fluid treatment means soaking in wine or vinegar or washing in water. Frying, baking and singeing are various methods of heat treatment. Among the tech-niques of combined fluid-heat treatment are steaming and boiling. Medicinal herbs or other substances are processed for the purpose of detoxication, enhancing their action, changing their properties or easy administration. Thus the herbs monkshood and the tuber of pinellia, which are poisonous, are soaked in water with ginger and vitriol to be detoxicated without harming their therapeutic potency. Glutinous Rehmannia which is "cold" in nature and cures febrile diseases in the unprocessed state, becomes "warm" and hematinic after steaming and drying several times. Other herbs and substances are processed to be purged of extraneous matter or to be reformed into pills or tablets for preservation.
Another significant respect in which Chinese pharmacology is unique is its compound prescription and the use of different parts of herbs for different therapeutic purposes. Generally speaking, doctors specializing in traditional Chinese medicine prescribe several or even dozens of different items for a dose, all of which are in balance for co-ordinated action. Different ratios of ingredients in a prescription and different dosages yield different effects. Compound prescriptions were first found in Nei Jing(Canon of Medicine) compiled in the 3rd century B.C. Zhang Zhongjing of the 3rd century A.D. offered a number of compound prescriptions in his Shang Han Za Bing Lun(Treatise on Febrile and Other Diseases). He prescribed cassia twigs with ephedra to induce perspiration in treating influenza or cold, and he used ephedra with almond and plaster for asthma and cough with high fever, while the same ephedra supported by the rhizome of large-headed atractylodes and ginger was given to patients suffering from swelling. Chinese angelica, as correctly indicated in Zhang's book, is a hematinic when the whole plant is used but its tips activate blood circulation. All these were discoveries made in long practice.
Different forms of processed medicine have been developed. The decoctions, pills and powders which we now use originated more than 2,000 years ago, when there were more than a dozen forms of medicine for internal and external administration.
Many specific medicines were found in ancient China. To those listed in Shen Nong's Materia Medica which we mentioned above may be added Java brucea for amoebic dysentery, chinaberry and stone-like omphalia for parasitic diseases, alga for goiter, animal liver for night-blindness, etc. The effectiveness of these specific substances has been confirmed by modern researchers.
What deserves special attention is the application in the 3rd century by the great surgeon Hua Tuo of an effervescing powder called mafeisan as an anaesthetic. Hua's initiative was of inestimable world significance.
Alchemy in ancient times also contributed to the advance in pharmacology, though that was not the aim set by the alchemists for themselves. Such alchemical products as mercury bichloride and mercuric oxide remain useful in surgery today.
