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HAN Yonggang
Abstract: The secret of traditional Chinese medicine (TCM) lies in the dosage that is used. In TCM prescriptions, the relative dosage ratio between medicinals is more important than the absolute dosage. There have been 4 major reforms of the weights and measures system in Chinese history, so the conversion between ancient and modern weights and measures is very important for the absolute dosage of medicinals. One sheng in the Han dynasty is approximately equal to 200 milliliters in modern times, and there is no debate on this point. The differences among conversions of the Han-dynasty liang into the modern gram are very large, ranging from 1 gram to 15.625 grams. The author suggests implementing small, medium, and large dose conversion algorithms according to different clinical situations.
Keywords: classical prescription; dosage; systems of weights and measures.
The effectiveness of TCM prescriptions is determined by the accuracy of the pattern diagnosis and the reasonability of the formula. A precisely targeted formula will definitely be effective! The ancient sages said that “the secret of TCM lies in the dosage that is used”, which highlights the importance of how medicinals are dosed. The ingredients in a formula are like the warp of a fabric and their dosage is the weft; when the warp and weft are combined, they can dispel disease.
1. Relative Dosage
In TCM prescriptions, the relative dosage ratio among medicinals may be even more important than the absolute dosage! Conversion methods between ancient and modern weights and measures may differ, so the absolute dosages of medicinals in a prescription may vary accordingly; this is acceptable as long as the absolute dosage is within a reasonable range. Excluding single-medicinal prescriptions, all TCM formulas are compound formulas. The key features of compound formulas are the combination of medicinal roles, namely sovereign, minister, assistant, and envoy, and the ratio among the dosages. In the “24 major and minor formulas for supplementing and draining the viscera and bowels” in Fu Xing Jue [Extraneous Secrets], the ratio between the sovereign and minister medicinals is 3:3, while the ratio between the sovereign and assistant medicinals is 3:1. This ratio is a relative dosage ratio between medicinals in these prescriptions that I believe is very reasonable and should be followed strictly in clinical practice.
In addition, Professor Huang Huang has proposed an interval ratio between the smallest and largest dosages; this also falls within the scope of relative dosage. In volume 1 of the Zhongguo Yaodian [Chinese Pharmacopoeia], the interval ratio between the smallest and largest dosages is 1:3; for example, if the smallest dosage is 3 grams, the largest would be 9 grams. However, in clinical practice, the actual interval ratio may in fact be very large. The results of a questionnaire survey of 330 famous TCM practitioners throughout China conducted by Professor Huang Huang showed that the interval ratios used by these practitioners typically ranged from 1:5 to 1:50 and could even reach 1:100. Therefore, Professor Huang Huang called for the interval ratio to be broadened to 1:5 or 1:10.
2. Absolute Dosage
Discussions of the absolute dosage of Chinese medicinals inevitably involve weights and measures, namely length, volume, and weight. Systems for measuring length developed around the time of the Shang or Yin dynasty, systems for measuring volume developed in the Warring States period, and systems for measuring weight developed between the mid- to late Spring and Autumn period and the middle of the Warring States period. After Qin Shi Huang unified the Central Plains of China, he implemented the first standardized system of weights and measures on a national scale. The Qin system continued to be used during the Han dynasty. Volume 21 of Han Shu [The Book of Han], entitled “Treatise on Rhythm and the Calendar”, states: “The weights are zhu, liang, jin, jun, and shi; they are used to balance things to know [how] light or heavy [they are]. They are based on the weight of the yellow bell [in the ancient Chinese musical system]. One yue holds 1200 grains of millet and weighs 12 zhu; 2 of these is a liang. [There are] 24 zhu in a liang. [There are] 16 liang in a jin. [There are] 30 jin in a jun. [There are] 4 jun in a shi.” So 24 zhu is 1 liang, 16 liang is 1 jin, 30 jin is 1 jun, and 4 jun is 1 shi.
The second standardization of the system of weights and measures happened in the Sui dynasty with a major breakthrough in terms of units; this system consisted of hao, li, fen, qian, liang, and jin.
The third standardization happened in 1928 when the government of the Republic of China established the “1-2-3 weight and measurement system for market use”, namely 1 liter = 1 sheng, 1 kilogram = 2 jin, and 1 meter = 3 chi. This served as an effective transition from the old system to the new international system. According to research by Fu Yanling, there was a decrease in dosages used during this measurement system reform in the Republic of China, but it did not attract attention. In the Qing dynasty, 1 jin was 600 grams, 1 liang was 37.5 grams, and 1 qian was 3.75 grams; the government of the Republic of China decided to adopt the international system and changed 1 jin to 500 grams, so 1 jin decreased by 100 grams and 1 liang became 31.25 grams, but the dosages given by practitioners when they wrote prescriptions did not change.
The fourth standardization happened in the People’s Republic of China. The “Regulations of the People’s Republic of China on Measurement (for Trial Implementation)”, issued in 1977, clearly stipulated that the International System of Units would gradually be adopted. According to the “Notice to Request Reports on Reforming TCM Prescription Dose Measurement Units”from the National Bureau of Standards and Metrology, which was authorized by the State Council on April 5th, 1977, starting on January 1st, 1979, the “gram” became the national standard unit of measurement for all TCM prescription dosages. Before the end of the year 1990, all industries throughout the country had to complete the transition to legal units of measurement.
China has a long and complex history, and there are both similarities and differences among the weights and measures used in various dynasties, so converting the absolute dosages of medicinals recorded in formula texts from different dynasties is a critical issue. In the 24 major and minor formulas for supplementing and draining the viscera and bowels listed in Fu Xing Jue, with the exception of the major and minor formulas for supplementing the heart, the dosage of the sovereign and minister medicinals is always 3 liang, while the assistant medicinal is always 1 liang. Fu Yanling’s summary of Shanghan Zabing Lun [On Cold Damage and Miscellaneous Diseases] found that 83.1% of individual medicinal dosages were between 1 and 4 liang. In the Wei, Jin, Sui, and Tang periods, the vast majority of medicinal dosages were likewise between 1 and 4 liang, and the Southern dynasty of Tao Hongjing’s time continued to use the Eastern Han dynasty system of weights and measures. The real question facing modern TCM practitioners is: how should 1 liang from Shanghan Zabing Lun or Fu Xing Jue be converted into modern grams? At present, there are a number of different perspectives.
(1) One liang equals 1 to 2 grams
Tao Hongjing’s Mingyi Bielu [Supplementary Records of Famous Physicians] says that “ancient weighing scales only had zhu and liang [units] and no fen [unit]; nowadays, 10 [grains of] millet is 1 zhu, 6 zhu is 1 fen, 4 fen is 1 liang, and 16 liang is 1 jin”. Based on the statement that “10 [grains of] millet is 1 zhu”, Wang Yiming measured the weight of 240 grains of millet and believes that 1 liang in the Han dynasty is roughly equivalent to 1 modern gram, with the maximum possible weight not exceeding 1.6 grams. Otsuka Keisetsu’s text Weights and Amounts of Medicinals states that “1 liang in the Han system is equivalent to 1.3 modern grams”, while Shimizu Totaro’s Pharmacological Research on Chinese Medicine says that “1 liang equals 1.42 grams”, and the Japanese text Third Revision of Japanese Quasi-Drug Formulas says “1 liang is equivalent to 2.0 modern grams”. This viewpoint has always been respected by Japanese Kampo practitioners such as Tamba Genkan and Yukiharu Awashima, most of whom support this theory, so it is the typical dosage currently used in Japanese Kampo prescriptions.
(2) One liang is equal to about 3 grams
Starting in the Song dynasty, reforms of the weights and measures system were implemented to switch from the traditional “zhu, fen, and liang” units to “qian and liang” decimal units, and the dengcheng and zicheng [weighing scales] appeared. It has been verified that in the Song dynasty, 1 jin was equivalent to between 634 and 640 grams, 1 liang was approximately 39 to 40 grams, and 1 qian was about 3.9 to 4 grams. One zi is ¼ of 1 qian, so it was roughly equivalent to 1 gram; 1 sheng in the Song dynasty was about 600 milliliters. In the Ming and Qing dynasties, 1 jin was approximately 578 to 579 grams, 1 liang was about 36 grams, and 1 qian was roughly 3.6 grams; 1 sheng in the Ming and Qing dynasties was about 1000 milliliters. The definitions of dose units used in modern textbooks are mainly influenced by Li Shizhen’s Bencao Gangmu [Herbal Foundation Compendium] from the Ming dynasty and Wang Ang’s Tangtou Gejue [Decoctions in Rhymes] from the Qing dynasty, which state that “the ancient system was different from the modern one; [in place of] the ancient 1 liang, [we] now use 1 qian. The ancient 1 sheng is the same as 2.5 ge nowadays.” One liang converted to the modern qian is about 3 grams, while 1 sheng is approximately equal to between 60 and 80 milliliters. Modern textbooks and prescriptions tend to follow this viewpoint.
Shanghan Lun Jiangyi [Lecture Notes on Shanghan Lun], edited by Chengdu TCM College in 1964, states, “Regarding standards for dosage, there are differences between ancient and modern [units]. In the Han period, 6 zhu equaled 1 fen and 4 fen equaled 1 liang; that is, 24 zhu equaled 1 liang. When applying a prescription, one must convert [the dosage] according to previous research, but it is even more important to rely on clinical practice. All references to ‘1 liang’ in this text are converted to 1 modern qian.” On this basis, 1 liang may be converted to 1 modern qian, which is about 3 grams. Later textbooks, including 5 editions of Shanghan Lun Jiangyi (the earliest version of a national standard textbook for advanced colleges of TCM), all adopted this perspective.
(3) One liang is equal to about 8 grams
In chapter 10 of Jingui Yaolüe [Essential Prescriptions of the Golden Coffer], entitled “Pulse, Symptoms, and Treatment of Abdominal Fullness, Cold Mounting, and Abiding Food”, after listing the prescription for“Aconite Main Root and Cinnamon Twig Decoction” (wū tóu guì zhī tāng), the text states “use 2 jin of honey and decoct until reduced by half. Remove the dregs, then dilute with 5 ge of Cinnamon Twig Decoction (guì zhī tāng) to make 1 sheng”. Based on the record of this decoction method, Chen Jiahua et al. believed that the volume of 1 jin of honey was 0.5 sheng (5 ge). Given that 1 sheng in the Eastern Han dynasty was equivalent to 198 milliliters, 0.5 sheng would be 99 milliliters, and testing shows that the specific gravity of raw honey is 1.27 grams per milliliter. From this it can be deduced that 1 jin in the Eastern Han dynasty was 126 grams and 1 liang was about 8 grams.
(4) One liang is equal to between 13.75 and 13.92 grams
In the late Qing dynasty, Wu Dacheng found that the mass of 1 Xinmang liang was 13.674644 grams for currency correction purposes, while Liu Fu measured it as 14.1666 grams using the Xinmang Jia measurement system. Wu Chengluo calculated the average of these two figures and thought that 1 Xinmang liang was equal to 13.92 grams. The Eastern Han dynasty used the Xinmang system. The results of Wu’s textual research have been relatively influential in recent years; the aforementioned data have been referenced in texts such as Zhongyi Mingci Shuyu Xuanshi [Interpretation of TCM Names and Terminology], edited by the China Academy of Chinese Medical Sciences and the Guangzhou University of TCM, as well as the appendix of Zhongyao Da Cidian [The Great Dictionary of Chinese Medicine].
Based on the excavation of multiple Eastern Han weighing devices, Qiu Guangming found that 1 jin in the Eastern Han dynasty was approximately equal to 222 grams and 1 liang was equal to 13.875 grams.
In China’s “973 Program” project entitled“Results on the Topic of Fundamental Research on Dose-Response Relationships in Famous Classical Formulas”, Fu Yanling thought that Zhang Zhongjing used the official scale to weigh medicinals in formulas. Therefore, according to Zhongguo Jishu Kexue Shi: Du Liang Heng Juan [History of Chinese Technology and Science: Weights and Measures], 1 jin in the Eastern Han dynasty was equal to 220 grams, so 1 liang was equal to 13.75 modern grams. Moreover, ancient scales from earlier dynasties were maintained in the Tang and Song periods for use in weighing valuable items like gold, silver, silk floss, and medicinals. They were called “gold and silver scales”, “silk floss scales”, or “medicinal scales”, but in fact they were all Han scales, the official scales of the Han dynasty.
The results of Fu, Qiu, and Wu’s research are all very similar to each other.
(5) One liang is equal to 6.96 grams
Shanghan Lun Yuyi [A Translation of Shanghan Lun], edited by the China Academy of Chinese Medical Sciences, referenced the standard conversion of 1 Eastern Han liang to 13.92 modern grams from Wu Chengluo’s Zhongguo Du Liang Heng Shi [A History of Chinese Weights and Measures]. However, it also referenced Su Jing’s Xinxiu Bencao [Newly Revised Herbal Foundation] from the Tang dynasty, which states that “ancient scales have been revived as the modern Southern [dynasty] scale. After the Jin [dynasty] scale began [to be used] in the late Han dynasty, 1 jin was divided into 2 jin and 1 liang was divided into 2 liang. Gold, silver, and silk floss are the same as medicinals; their weight is negligible. Among the ancient formulas, only [those of Zhang] Zhongjing already use the modern scale. If one were to use the ancient scale to decoct them, there would be too little water, so [we] know [Zhang] did not use the revived [ancient] scale and was familiar with the modern one.” Based on this record, Shanghan Lun Yuyi claimed that there was a medicinal scale in the Eastern Han period with units that were half those of conventional scales at that time and therefore converted 1 liang in Shanghan Lun to 6.96 grams.
(6) One liang is equal to 15.625 grams
Ke Xuefan et al. performed calculations based on data about the “Guanghe Dasinong [Major Agricultural Department] Copper Weight”in the Zhongguo Gudai Du Liang Heng Tuji [Chinese Ancient Weights and Measures Atlas] edited by the Chinese National Institute of Metrology. This weight is currently housed in the National Museum of China. It is 7.6 centimeters high and the diameter of its base is 10 centimeters, with a mass of 2996 grams. It is hemispherical in form and features a square hole punched by an “inspection seal”. It bears an inscription that reads: “Dasinong [The Major Agricultural Department] issued an imperial edict in the early morning on the day of the autumnal equinox: to unify measurements, equalize weights, reconcile volumes, and rectify scales, copper measuring scoops, measuring vessels, scales, and rulers have been specially made for all the provinces in accordance with the yellow bell tuning system and the Jiu Zhang Suanshu [9 Chapters on the Mathematical Art], in order to equalize differences in length, weight, and size, to be used every day of the week, so that the entire country is unified. Created on the 23rd day of the second month of the second year of Guanghe by Dasinong [official] Cao Ling, auxiliary official Chun Yugong, right storehouse leader Chuan Zhuyin, and historian Han Hong.” “Guanghe” is the era name of Liu Hong, Emperor Ling of Han; the second year of Guanghe is the year 179, which is in the same period as Zhang Zhongjing. From this inscription, we know that this weight was part of the standard issued by the central government at that time to unify all weighing devices throughout the country. According to the precise system of unit values and procedures for weight classes in the Qin and Han periods, this copper weight should be a 12-jin weight and its standard mass should be 3000 grams. On this basis, 1 jin in the Eastern Han dynasty was 250 grams and 1 liang was 15.625 grams.
In fact, according to the Yijing [Book of Changes], TCM, and Daoist theory, one can also infer that 1 Eastern Han liang converts to 15.625 modern grams. Chapter 25 of Huangdi Neijing [The Yellow Emperor’s Inner Canon], entitled “Treatise on Treasuring [Heaven’s] Mandate to Preserve the Body”, states: “Covered by heaven and carried by earth, all beings have their place and none are more noble than humans. Humans are born from the qi of heaven and earth, and mature according to the laws of the 4 seasons […] Indeed, humans are born on earth and their fate relies on heaven. The combined qi of heaven and earth is what is called ‘humankind’.” In TCM and Daoism, it is believed that a person comes to life by receiving the qi of heaven and earth as well as the qi of their parents. The number of qi terms in the circumference of heaven is 360; if one adds to this the number of qi terms of the father (12) and that of the mother (12), then the total number of qi terms for a person is 384, which corresponds to the 384 lines in the 64 hexagrams of Yi Jing. One jin in the Han dynasty is equal to 16 liang, which is equal to 384 zhu. If 1 jin converts to 250 modern grams, then 384 zhu divided by 16 liang equals 24 zhu, so 1 liang is 24 zhu; 250 grams divided by 16 liang equals 15.625 grams. Thus, 1 liang converts to 15.625 modern grams.
(7) Small, medium, and large dose conversion algorithms
I believe that the most powerful direct evidence comes from archeological artifacts; therefore, Ke Xuefan’s calculation performed using the “Guanghe Dasinong Copper Weight”, which found that 1 liang equals 15.625 grams, is reliable. However, given the fact that Xinxiu Bencao mentions that the medicinal scale units used in the Eastern Han period were half those of the conventional scale, half of 15.625 grams is 7.8125 grams, so it is approximately 8 grams.
Volume 1 of Beiji Qianjin Yaofang [A Thousand Gold Pieces Emergency Formulary], entitled “Treatises on Medicine”, states: “If the disease is mild, one must use lower doses of medicinals; if the disease is severe, then the dose will be higher.”
As a clinical practitioner of TCM, I value simplicity and practicality. Therefore, regarding the conversion of dosages of classical remedies in Shanghan Zabing Lun and Fu Xing Jue, my recommended principles are as follows: for typical cases of external contraction and miscellaneous internal damage diseases, convert 1 liang in classical remedies to 8 modern grams. For externally contracted heaven-current diseases, i.e., diseases that are highly contagious, epidemic, and deadly, or in cases with critical, acute, or severe symptoms, convert 1 liang in classical remedies to 15 modern grams. One may also use the principle of doubling the dose of the first preparation to stop the progression of the disease and reverse its course. Treat external contraction like an army general; use strong penalties in chaotic situations. This is why it is said that strong doses can treat deep-rooted disease! To regulate the body and mind in conditions of subhealth, small doses are adequate; convert 1 liang in classical remedies to 3 grams to treat internal damage and prolong life.
This 3-level dosage recommendation involves “adjusting the dose according to the disease”. While it does not blindly emphasize large doses, it also does not blindly emphasize minuscule doses. Rather, it emphasizes the reasonable dosage of medicinals. Using the small dose conversion algorithm, 1 liang converts to 3 grams. Using the medium dose conversion algorithm, 1 liang converts to 8 grams. Using the large dose conversion algorithm, 1 liang converts to 15 grams.
(8) One sheng is equal to 200 milliliters
Volume 21 of Han Shu, entitled “Treatise on Rhythm and the Calendar”, states: “The [units of] volume are the yue, ge, sheng, dou, and hu; they are used to measure amounts. They are based on the cylinder of the yellow bell; its volume was measured by its length, the cylinder was filled with 1200 mid-sized grains of millet, and then well water was added to level it out. [The volume of this] cylinder is the [unit] ge; [there are] 10 ge in a sheng, 10 sheng in a dou, and 10 dou in a hu. These are the 5 Jia units of volume.”
This passage defines the units of volume: there are 2 yue in 1 ge, 10 ge in 1 sheng, 10 sheng in 1 dou, and 10 dou in 1 hu.
The Shanghai Museum houses the “Guanghe Dasinong copper hu [measuring vessel]” that was unearthed in Huizhou, Hunan province, in 1815. This vessel is made of copper and has a barrel-like shape with a round mouth, straight walls, and a flat bottom. Its mouth and bottom are slightly flared and the walls of its midsection feature symmetrical short, round handles. There are 3 cord marks around its midsection; near the handles there is a small box used for embedding an inspection seal that does not contain any inscription. Two identical inscriptions, each containing a total of 89 Chinese characters, are incised along the rim of the mouth and base: “ Dasinong [The Major Agricultural Department] issued an imperial edict in the early morning on the day of the autumnal equinox: to unify measurements, equalize weights, reconcile volumes, and rectify scales, copper measuring scoops, measuring vessels, scales, and rulers have been specially made for all the provinces in accordance with the yellow bell tuning system and the Jiu Zhang Suanshu [9 Chapters on the Mathematical Art], in order to equalize differences in length, weight, and size, to be used every day of the week, so that the entire country is unified. Created on the 23rd day of the second month of the second year of Guanghe by Dasinong [official] Cao Ling, auxiliary official Chun Yugong, right storehouse official Chuan Zhuyin, and historian Han Hong.” Two Chinese characters that read “Yang’an” are inscribed on the wall of the vessel. “Dasinong” was one of the 9 ministers and was in charge of the nation’s main financial revenues and expenditures, including rent, taxes, money, grain, salt, and iron. In the Eastern Han dynasty, “Yang’an” was located in Runan prefecture, Yuzhou. This measuring vessel was created under the supervision of various levels of officials, including Dasinong, an auxiliary official, and a right storehouse official, and was sent to Yang’an county for use. Its actual volume is 20400 milliliters, so 1 sheng converts to 204 milliliters.
The National Museum of China houses the “Jianwu Dasinong level hu [measuring vessel]”. It is barrel-shaped with a height of 24.4 centimeters and the diameter of its mouth is 34.5 centimeters. There are symmetrical short handles on both sides of its midsection. A line of text is inscribed on the outer wall of its midsection: “Dasinong level hu [measuring vessel], created in the first month of the 11th year of Jianwu”. “Jianwu” is the era name of Liu Xiu, Emperor Guangwu of Han; the 11th year of Jianwu is the year 35. The actual volume of the vessel is 19600 milliliters, so 1 sheng converts to 196 milliliters, which is basically the same as the Wang Mang [or Jia/Xinmang] measuring system. Above the handles there is a box that protrudes, which was originally used to insert the inspection seal once officials had verified its volume. Surviving inspection seals from the Eastern Han dynasty include the words “leveled according to official law”; “leveled” here refers to the standard volume verified by the official. Thus, a “level hu” is a standard hu.
Other weights and measurement devices issued by the Dasinong that have been found up to now include a copper Dasinong level ge [measuring vessel] created in the 3rd year of Yongping (i.e., the year 60) and a copper Dasinong level dou [measuring ladle] created in the 3rd year of Yuanchu (i.e., the year 116). Testing of these vessels has found that the volume of 1 sheng is about 200 milliliters. At present, there is no controversy on this point.
References
1. Fan Ying, Jiang Kaiyun, Zhang Hongmei. Zhongyao yaodui peifang lilun ji yingyong [Theory and application of Chinese medicinal pairs]. Shenyang: Liaoning Kexue Jishu Chubanshe [Liaoning Science and Technology Publishing House], 2015
2. Zhu Fuhua, Yang Zhichun, Fan Ping. Zhongyi zhongyao jiaoyao yanjiu [Research on Chinese medicinal triads in TCM]. Mingyi mingfang, yanfang zuyao peiwu jiqiao [Techniques for combining medicinals from famous doctors, famous formulas, and empirical formulas]. Xi’an: Shaanxi Kexue Jishu Chubanshe [Shaanxi Science and Technology Publishing House], 2009
3. Yi Zhibiao. Fu xing jue wu zang yongyao fayao [Medicinal dosing methods for the 5 viscera in Fu Xing Jue]. Yaoxing tanzhen [Discovering the truth about medicinal properties]. Beijing: Xueyuan Chubanshe [Academy Press], 2013
About the Author: Han Yonggang earned his doctoral degree from the Institute of Basic Research in Clinical Medicine at the China Academy of Chinese Medical Sciences. He studied under Wang Yongyan, a member of the Chinese Academy of Engineering, and Professor Gao Sihua, former president of Beijing University of Chinese Medicine. He has worked in the UK since 2009, where he is currently employed at Chelsea Natural Health Clinic and the London Academy of Chinese Acupuncture. He serves as vice-chairman of the EU TCM Wuyunliuqi Association and is a member of the World Classic Chinese Medicine Association Expert Committee. He is also a standing member of the World Federation of Chinese Medical Societies Expert Committee on Prescription-Dose Effects and an executive council member of the World Federation of Chinese Medical Societies Targeted Diagnosis and Treatment Committee. In addition, he is the head of the Education and Academic Department of the Huatuo International Medical Research Association and an academic council member of the Chinese Acupuncture and Herbal Medicine Alliance UK (CAHMA). He has published 8 academic works on TCM, including Records of Medical Minds: Traditional Chinese Medical Treatment for Rheumatism, Records of Medical Minds: Traditional Chinese Medical Treatment for Diabetes, Records of Medical Minds: Traditional Chinese Medical Treatment for Cerebrovascular Diseases, Guide to the Diagnosis and Treatment of Rheumatism, and Guide to the Use of Chinese Medicine in the Treatment of Gynecological Diseases. He has 28 years of clinical experience with providing TCM treatment, rehabilitation, and health maintenance in the areas of internal medicine, gynecology, and pain management. He is especially adept at treating male and female infertility, anxiety, and depression.
論經方的劑量
韓永剛
【摘要】中藥的不傳之秘在於用量。中藥處方中，藥物之間的相對劑量比絕對劑量更加重要。中國曆史上有4次重大的度量衡制度改革，因此對於藥物的絕對劑量，度量衡的古今換算非常重要。漢代1升約等於現代200ml，這一點目前沒有爭論。漢代1兩折算為現代的g，則差別很大，在1g至15.625g之間。筆者建議根據臨床面臨的不同情況，實施小、中、大劑量折算法。
【關鍵詞】經方；劑量；度量衡。
中藥處方的有效性取決於辯證的准確性和組方的合理性，精准組方，一定有效！前賢有云“中藥的不傳之秘，皆在用量”，可見藥量之重要。方藥為經，藥量為緯，經緯結合，方能祛病。
一、相對劑量
1. Relative Dosage
中藥處方中藥物之間的相對劑量甚至比絕對劑量更加重要！度量衡的古今換算方法或許不同，處方中藥物的絕對劑量則不同，絕對劑量只要在合理的範疇之內就可以。單味藥處方之外均為復方，復方的關鍵在於藥物的君臣佐使組合以及藥量之間的比例。《輔行訣》“臟腑補瀉24方”的君藥和臣藥之間的比例是3:3，君藥和佐藥之間的比例是3:1，這個比例是處方藥物之間的相對劑量比，筆者認為是非常合理的，應當在臨床中堅決貫徹執行。
另外，黃煌教授還提出一個最小量與最大量的區間比，這也屬於相對劑量的範疇。《中國藥典·一部》最小量和最大量的區間約是1:3，例如最小量是3克，則最大量是9克。但是臨床實際的區間比實際很大，黃煌教授所做的330名全國名中醫的問卷調查，結果顯示這些名中醫常用藥物的區間一般在1:5到1:50，甚至有1:100。因此黃煌教授呼吁將區間比放寬到1:5、1:10。
二、絕對劑量
2. Absolute Dosage
談到中藥的絕對劑量，必然要涉及度量衡，即尺度、容量、權衡。度制約在商殷，量制約在戰國，衡制約在春秋中晚期到戰國中期。自秦始皇統一中原後，在全國範圍內第一次實行了統一的度量衡制｡漢承秦制，《漢書·律曆志》：“權者，銖、兩、斤、鈞、石也，所以稱物平施，知輕重也。本起於黃鐘之重。一龠容千二百黍，重十二銖，兩之為兩。二十四銖為兩。十六兩為斤。三十斤為鈞。四鈞為石。”24銖為1兩，16兩為1斤，30斤為1鈞，4鈞為1石。
度量衡制的第二次統一發生在隋代，單位上有重大突破，使用了毫、釐、分、錢、兩、斤制｡
第三次統一發生在1928年，中華民國政府確定了“一二三權度市用制”，即1公升=1市升，1公斤=2市斤，1米=3市尺，這樣有效地從舊制向新制國際單位的過渡｡根據傅延齡先生的研究，民國的這次度量衡改革出現了用量下降，但是並未引起人們的注意。清代一斤是600克，一兩是37.5g，一錢是3.75g；民國政府決定採用國際制度，改為500g為一斤，則1斤減少了100g，一兩就變成了31.25g，但是醫生開方時劑量並未改變。
第四次統一發生在新中國，1977年頒發的《中華人民共和國計量管理條例(試行)》已明確規定要逐步採用國際單位制。根據1977年4月5日國務院批轉國家標準計量局等單位《關於改革中醫處方用藥計量單位的請示報告的通知》，從1979年1月1日起，全國中醫處方用藥的計量單位一律採用以“g”為單位的國家標準｡1990年年底以前，全國各行業應全面完成向法定計量單位的過渡。
中國的曆史源遠流長，各個朝代的度量衡有同有異，如何折算不同朝代方書中所記載藥物的絕對劑量就是一個關鍵問題。《輔行訣》臟腑大小補瀉方24首，大小補心方之外的處方的君藥、臣藥的劑量都是3兩，佐藥都是1兩。傅延齡先生總結《傷寒雜病論》83.1%的藥味用量是在1兩到4兩之間，魏晉隋唐時期的絕大多數藥物用量也是在1兩到4兩之間，陶弘景所在的南朝沿用東漢的度量衡制度。現代中醫師所面臨的現實問題是：《傷寒雜病論》和《輔行訣》中的1兩究竟折合現代多少克？目前有多種不同的認識。
（一）一兩相當於1g至2g
(1) One liang equals 1 to 2 grams
陶弘景《名醫別錄》“古秤唯有銖兩而無分名，今則以十黍為一銖，六銖為一分，四分成一兩，十六兩為一斤”。王伊明依據“十黍為一銖”之說，稱量 240粒黍的重量後，認為漢代1兩合今之1g左右，最大不超過1.6g。大冢敬節《藥物的權量》“漢制一兩，合今1.3克”，清水藤太郎《國醫藥物學研究》“一兩等於1.42克”，日本《第三改正日本准藥局方》“一兩合今2.0克”。此類觀點一直被日本漢方學家所遵循，如丹波元簡、粟島行春多持此論，為目前日本漢方的常用量。
（二）一兩相當於3g左右
(2) One liang is equal to about 3 grams
自宋代起度量衡實施變革，由傳統的“銖分兩”進位改為“錢兩”的十進位制，並出現了戥秤、字秤。經證實，宋元時期的1 斤約合634～640g，1兩約為39～40g，1錢約為3.9～4g，1字是1錢的1/4，約合1g；宋元時的1升約600毫升。明清時期的1斤約合578～579g，1兩約36g，1錢約3.6g；明清時的1升約1000毫升。如今教科書應用的劑量單位定義主要受明代李時珍《本草綱目》和清代汪昂《湯頭歌訣》的影響，“今古異制，古之一兩，今用一錢可也。古之一升，即今之二合半也。”1兩折合今1錢約3g，1 升相當於今之60～80ml。今之教材，時下處方，多遵此說。
1964年成都中醫學院編寫的《傷寒論講義》“關於劑量之標準，古今不一，漢時以六銖為一分，四分為一兩，即二十四銖為一兩。處方應用時，一方面根據前人考證的量制折算，更重要的是依據臨床實踐。凡論中云一兩者，折今約一錢。”據此1兩折合今之一錢，約3g。此後的教材，包括五版教材（全國高等中醫學院最早版統一教材）《傷寒論講義》均採用了此說。
（三）一兩相當於8g左右
(3) One liang is equal to about 8 grams
陳家驊等根據《金匱要略·腹滿寒疝宿食病脈證並治》篇中“烏頭桂枝湯”方後“以蜜二斤，煎減半，去滓，以桂枝湯五合解之，令得一升”有關煎服法的記載，認為1斤蜜的容積為0.5升（五合），按東漢1升折合198ml，0.5升為99ml，同時又測得生蜜比重為1.27g/ml。推測東漢1斤合126g，1兩合8g弱。
（四）一兩相當於13.75g～13.92g
(4) One liang is equal to between 13.75 and 13.92 grams
吳承洛將清末吳大澄以貨幣校得新莽1兩為13.674644g與劉復以新莽嘉量測得新莽1兩為14.1666g兩個數值進行平均，認為新莽1兩為13.92g，東漢承新莽之制。吳氏考證結果對近代影響較大，中醫研究院、廣州中醫學院合編《中醫名詞術語選釋》、江蘇新醫學院《中藥大辭典·附篇》等均引用了上述數據。
丘光明據多件東漢時期出土衡器考證東漢1斤約定為222g，1兩為13.875g。
國家“973計划”項目“以量-效關係為主的經典名方相關基礎研究課題成果”，傅延齡先生認為張仲景對於方藥的計量用的是官秤，因此按照《中國技術科學史·度量衡卷》，東漢時期1斤為220g，則一兩為現代13.75g。並且唐宋時期保留的以前朝代的古秤，用來秤金銀、絲綿、藥等貴重物絲綿品，被稱為金銀秤、絲綿秤、藥秤，其實都是漢秤，漢代官秤。
傅氏、丘氏和吳氏的研究結果非常接近。
（五）一兩相當於6.96g
中國中醫研究院編著的《傷寒論語譯》，一方面引用吳承洛《中國度量衡史》關於東漢1兩合今之13.92g的標準，一方面根據唐代蘇敬《新修本草》“古秤皆復，今南秤是也。晉秤始，後漢末以來，分一斤為二斤耳，一兩為二兩耳。金銀絲綿，並與藥同，無輕重矣。古方唯有仲景而已涉今秤，若用古秤作湯，則水為殊少，故知非復秤，悉用今者爾”的記載，認為東漢時期有藥秤，是當時常用秤的一半，將《傷寒論》中的1兩折合今之6.96g。
（六）一兩相當於15.625g
(6) One liang is equal to 15.625 grams
柯雪帆等根據國家計量總局《中國古代度量衡圖集》中“光和大司農銅權”的有關資料進行了核算。此權現藏中國曆史博物館，高7.6cm，底徑10cm，重2996g，權呈半圓形，權身有一鑲“檢封”的方穴。器身有銘文“大司農以戊寅詔書，秋分之日，同度量，均衡石，捔斗桶，正權概，特更為諸州作銅斗、斛、稱、尺、依黃鐘律曆，九章算術，以均長短、輕重、大小，用齊七政，令海內都同。光和二年閏月廿三日，大司農曹祾，丞淳于宮，右倉曹椽朱音，史韓鴻造。”“光和”為漢靈帝劉宏年號，光和二年為公元179年，與張仲景為同年代。從銘文可知，此權為當時中央政府為統一全國衡器而頒佈的標準。銅權，按秦漢密制的單位量值和權的量級程序，此權當為12斤權，標準重量當為 3000g。據此東漢1斤合今之250g，1兩合今之15.625g。
其實根據《易經》、中醫和道家的理論，也可以推導出漢代1兩折合現今15.625g。《黃帝內經·寶命全形論》“天覆地載，萬物悉備，莫貴於人，人以天地之氣生，四時之法成……夫人生於地，懸命於天，天地合氣，命之曰人。”中醫和道家認為人得天地之氣和父母之氣而生，周天氣數是360，再加上父親氣數12和母親氣數12，人之氣數總計是384，與《易經》的64卦之384爻相對應。漢代1斤=16兩=384銖，1斤折合現今250g，則384銖/16兩=24銖，1兩是24銖；250g/16兩=15.625g，1兩折合現今的15.625g。
（七）小、中、大劑量折算法
筆者認為，實物考古是最有力的直接證據，因此柯雪帆先生通過“光和大司農銅權”所做核算，1兩合今之15.625g是值得信賴的。但是《新修本草》提出東漢時期的藥秤是當時常用秤的一半，這樣15.625g的一半就是7.8125g，約等於8g。
《備急千金要方·醫學諸論》“病輕用藥須少，病重用藥即多。”
做為一名臨床中醫，筆者推崇簡單實用，因此對於《傷寒雜病論》和《輔行訣》中的經方量的折算，筆者的建議原則如下：對於普通外感病和內傷雜病，按照經方一兩約等於現代8g的方式折算；對於外感天行病，也就是具有強烈傳染性、流行性和致死性的疾病，或者是危症、急症、重症，則按照經方一兩約等於現代15g的方式折算。還可以使用首劑加倍的原則，從而截斷發展，扭轉病勢。治外感如將，亂世用重典，重劑起沉痾，此之謂也！而對於調理身心的亞健康狀態，小劑量即可，按照經方一兩折算為3g即可，治內傷如相，人登壽域。
這樣的三個層次用量建議，“隨病施量”，既不是一味地強調大劑量，也不是一味地強調輕靈小劑量，而是強調合理用藥。小劑量折算法，一兩折算為3g；中劑量折算法，一兩折算為8g；大劑量折算法，一兩折算為15g。
（八）一升相當於200ml
《漢書·律曆志》：“量者，龠、合、升、斗、斛也，所以量多少也。本起於黃鐘之龠，用度數審其容，以子穀秬黍中者千有二百實其龠，以井水准其概。合龠為合，十合為升，十升為斗，十斗為斛，而五量嘉矣。”
規定了容量單位，二龠為一合，十合為一升，十升為一斗，十斗為一斛。
上海博物館收藏有1815年河南睢州出土“光和大司農銅斛”，此斛用銅制成，作圓桶狀，圓口，直壁，平底，上口及底部略侈，腹壁中部有對稱短圓柄，腰部圍三道弦紋，近柄處有鑲檢封之用的小方框，上無銘文。口沿、底沿皆陰刻相同銘文一周“大司農以戊寅詔書，秋分之日，同度量，均衡石，捔斗桶，正權概，特更為諸州作銅斗、斛、稱、尺、依黃鐘律曆，九章算術，以均長短、輕重、大小，用齊七政，令海內都同。光和二年閏月廿三日，大司農曹祾，丞淳於宮，右倉曹椽朱音，史韓鴻造。”共計89字，器壁陰刻“陽安”二字。“大司農”為九卿之一，掌管國家租、稅、錢、穀、鹽、鐵等主要財政收支。“陽安”東漢屬豫州汝南郡。此量斛由大司農、丞、右倉曹等各級官吏監制，發至陽安縣使用。實測容積為20400ml，折算1升合204ml。
中國國家博物館收藏有1953年甘肅省古浪縣出土的“建武大司農平斛”，圓桶形，高24.4cm，口徑34.5cm，腹左右有對稱短柄。腹部外壁刻銘文一行“大司農平斛，建武十一年正月造”。“建武”為東漢光武帝劉秀年號，建武十一年即公元35年。實測容積為19600ml，折算1升合196ml，與王莽之制基本一致。柄上方有凸起方框，原用來嵌入官府檢定容積後所作的檢封。傳世漢代檢封有“官律所平”等字，“平”指官府檢定的標準量值。“平斛”即為標準之斛。
迄今所見由大司農頒發的度量衡器，還有永平三年（公元60年）銅質的大司農平合，元初三年（116年）銅質的大司農平斗。經實測各種量器1升的單位量值均在200ml左右。這一點目前沒有爭論。
【參考文獻】
1.范穎,姜開運,張紅梅.中藥藥對配方理論及應用.沈陽:遼寧科學技術出版社,2015
2.朱富華,楊志春,樊平.中醫中藥角藥研究.名醫名方、驗方組藥配伍技巧.西安:陝西科學技術出版社,2009
3.衣之鏢.輔行訣五臟用藥法要.藥性探真.北京:學苑出版社,2013
【作者簡介】韓永剛，中國中醫科學院臨床醫學基礎研究所博士研究生，師從中國工程院王永炎院士和原北京中醫藥大學校長高思華教授。2009 年赴英國工作至今，現就職於Chelsea Natural Health Clinic和倫惇中醫針灸學院。擔任歐洲中醫五運六氣學會副會長，世界經典中醫學會專家委員會委員，世界中聯方藥量效專業委員會常務理事，世界中聯態靶辨治專業委員會常務理事，世界中醫五運六氣學會聯合會理事，世界華佗醫學研究會教育和學術部長，英國中國聯盟學會學術理事。出版《醫學傳心錄：名老中醫治療風溼病經驗》、《醫學傳心錄：名老中醫治療糖尿病經驗》、《醫學傳心錄：名老中醫治療腦血管病經驗》、《風溼性疾病診斷治療指南》、《婦產疾病臨床常用中藥指南》等中醫學術著作8部。臨床工作28年，從事內科、婦科、疼痛科疾病的中醫藥治療和康復保健，尤其擅長治療男女不孕不育症，焦慮症、抑鬱症等。
