| It is definite that the prescriptions in Han and Tang dynasties had large dosages. Most of the herbs recorded in the works of Han and Tang dynasties were measured by Jin or Liang, when converted into gram, the dosage of Single herb spread from tens of grams to hundreds of grams. While dosages of herbs recorded in the books of Song dynasty, if taken several Qian powder each time, were no more than tens of grams when converted into gram, the dosage of single herb was slighter. In contrast, the clinical dosage of medicine in Song dynasty decreased more significantly than that in the Han and Tang dynasties. In view of this phenomenon, Professor Fu Yan-iing put forward the idea of "The Three Gorges Dam" of dosage flow in Chinese herbs, which was as a metaphor to the phenomenon of significant decrease of clinical dosages of the herbs in Song dynasty. What is the reason for "the Three Gorges Dam"? In answering this question, people often quoted the opinions of Pang An-shi, described in his book named Shang Han Zong Bing Lun. He believed that in the late Tang and Five dynasties, there were great shortage of herb resources and inconvenient transportation of the herbs because of chaos caused by wars. In order to save herb resources, traditional Chinese medicine (TCM) practitioners selected decocting powder pattern instead of decoction. However, what are the true reasons for clinical dosage decrease in Song dynasty? It is obvious that explanation only by Pang An-shi is not enough to answer the question. The thesis endeavors to give detailed explanations from the perspective of history, describing the real appearance of dosage decrease of the herbs in Song dynasty and exploring the influences of social background, economic level, political policy and ideology on the dosages of the herbs and prescriptions.After research, the following conclusions can be drawn in the paper.First of all, influences of prevalence of boiling powder on the clinical dosages of prescriptions. Decoction with large dosages in Han and Tang dynasties were replaced by boiling powder with small dosages in Song dynasty, which had a great impact on the clinical dosages of prescriptions. Through the representative works written or compiled by TCM practitioners in cold damage school and government in Song dynasty, this part mainly focuses on the applications of decocting powder pattern and conventional decoction pattern by TCM practitioners in Song dynasty. It contains; the definition of decocting powder by TCM practitioners in Song dynasty, dosage of decocting powder and methods to boil and take, indications of decocting powder, textual research on dosage conversion in ancient and modern time, and decoction dosage conversion in classical formula, etc. and how they replaced decoction with decocting powder, the dosage changes of prescriptions after implementing decocting powder. The conclusions are prevalence of decocting powder originated from Tang and Five dynasties, but became fixed in the Southern and Northern dynasties. TCM practitioners in Song dynasty didn’t distinguish decoction or decocting powder, replacing decoction with decocting powder is the principal reason for the decrease of clinical dosages of prescriptions. Decocting powder being prevalent, there were still several TCM practitioners adhering to use decoction with large dosages, which had little effect on the overall dosages of prescriptions.Secondly, the influences of supply and demand of medical herbs on the clinical dosages of prescriptions. The supply of medicinal herbs including production and circulation will be talked about, and then the social demand of the medicinal herbs in Song dynasty. The modes of production of medicinal herbs in Song dynasty contained collecting from nature, growing in nursery gardens in a small scale, managing by specialized medicinal herb growers, and importing from other branches related with agriculture, neighboring countries, and the overseas. With respect to circulation of medicinal herbs, on one hand, the domestic herb markets were thriving, especially in herb-rich regions and the capital, the circulation of medicinal herbs in different areas became more convenient. On the other hand, medicinal herbs were essential items in government monopoly markets from neighboring countries and town ship trades from the overseas. However, the growth of the medicine supply was difficult to meet the needs of herb demand, which was ascribed to the following reasons. The territory in Song dynasty was limited, but the population was continuously increasing. There was a contradiction between limited land sources, confined herb sources and booming population. What’s more, the frequent natural disasters and epidemic diseases and great development of social medical relief demanded a large number of herb sources in Song dynasty. In addition, redundant soldiers due to recruiting system and development of army medicine, large quantities of medicinal materials were also needed.Thirdly, the influences of medical heritage on the clinical dosages of prescriptions. The modes of medical heritage in Han and Tang dynasties included master-apprentice and from generation to generation within family, which were of great closure. During that time, it was hard to get a book, so if a TCM practitioner got a book, he would read it again and again. Under those circumstances, no matter the medical theories or practicing techniques could be kept in the original appearance as well as the habit of prescriptions and clinical dosages. Since the Song dynasty, due to great importance from government and development of printing, the mode of medical heritage changed from closure to open. The medical works being spreading, anyone was able to learn medical knowledge by reading these books. The main type of medical books popularized in Song dynasty was medical formularies, which were originated from empirical formulas in folk. This was different from the classical formulae in Han and Tang dynasties. Take the clinical dosages of prescriptions for example, medication specifications in a small dosage were implemented in medical books and school education, and large dosages of prescriptions were unfamiliar by most TCM practitioners. Although specific and strong efficacy in large-dosage decoctions, TCM practitioners couldn’t risk applications unless they were qualified. During that period, the current prescriptions were in popular, and the classical formulae and the decocting method were ignored by TCM practitioners in Song dynasty.Finally, the influences of herb combination on the clinical dosages of prescriptions. In ancient time, the disease conditions were relatively simple and herb species for clinical usage were limited. Therefore, most formulae were with the characteristics of specific and strong efficacy. While in the Song dynasty, the disease conditions became complicated and herb species greatly added, which led to the number of herbs in a prescription increased but the dosage of each herb decreased.Decline of clinical dosages of prescriptions in Song dynasty has a far-reaching impact on future generations. It broke the tradition that decoction in Han and Tang dynasties must be used in large dosage, and pioneered for small-dosage decoction. It has been proved that replacing large-dosage decoction with small-dosage decocting powder whose effective ingredients can be easier to dissolve out, which greatly improves utilization and saves herb resources. In clinic, low-dosage decocting powder can obtain a reliable effect, which can achieve satisfactory results in the treatment of lots of diseases. In addition, a few diseases can be applicable in small-dosage decocting powder. However, due to its slight dose, it is almost impossible to treat diseases in severe conditions. Besides, the dosages of herbs and prescriptions are different in traditional decoctions, which may display in several, decades or tens of times. Whereas in Song dynasty,3to5Qian was taken each time for small-dosage decocting powder, and the dosage difference among herbs is removed completely. |
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