2 Purgative Formulas

Purgative formulas are mainly composed of purgative medicinals, and bear the functions of freeing defecation, attacking accumulations, purging excess, removing stagnancy, and purging heat and water, etc., and are used for interior excess syndromes. They are referred to as “formulas for attacking the interior” (攻里之剂) in the Medical Formulas Collected and Analyzed by Wang Ang, and were categorised as“purging formulas” (攻下门) which belong to the category of the “purgative method” (下法)of the eight methods in the Practical Usage of Established Formulas by Wu Yi-luo.

Regarding the origin and development of purgative formulas, the Basic Questions - Great Treatise on the Correspondences and Manifestations of Yin and Yang indicated: “ For symptoms of abdominal fullness, purge it internally ” (中满者，泻之于内); “ For cases of excess, purge it by dispersion ” (其实者，散而泻之). Another record in the Basic Questions - Treatise on Heat ( Sù Wèn - Rè Lùn , 素问·热论)stated that: “ Fullness within three days could be treated by diaphoretics; while fullness beyond three days could be cured by purgation ” (其未满三日者，可汗而已；其满三日者，可泄而已). This serves as the theoretical evidence and applying principles of purgative formulas. The Discussion on Cold Damage and the Essentials from the Golden Cabinet by Zhang Zhongjing from the Eastern Han Dynasty adopted the formulating theory of the “ purgative method ”(下法) from the Inner Classic and advanced its development by creating thirty-one purgative formulas. According to their different purgative functions, these formulas are divided into various types i. e. drastic purgation, light purgation, laxation, moistening purgation, etc. and each one has its own strict indications and contraindications. Among those, the purgative heuristic method, which recommends the use of Xiăo Chéng Qì Tāng (Minor Qi-Coordinating Decoction, 小承气汤) as the main representative formula for syndrome requiring the purging method, has clinical significance even today and is the pioneer of syndrome differentiation and treatment for the interior excess syndrome. These effective purgative formulas and the relevant clinical experience drew much attention and were popularized widely in the transitional period from the Jin Dynasty to the Tang Dynasty. During the period of the Song, Jin and Yuan Dynasties, Liu Wan-su summarized the experience of treating heat diseases with the combination of the purgative method with the clearing method and created original formulas such as Liáng Gé Săn (Diaphragm-Cooling Powder, 凉膈散), Shuāng Jiĕ Săn (Double Resolution Powder), and Fáng Fēng Tōng Shèng Săn (Saposhnikovia Sage-Inspired Powder), for relieving symptoms of both the exterior and interior, diffusing and freeing heat accumulation, these formulas were considerably unique; Zhang Cong-zheng advocated dispelling evils in treatment, and emphasized the theory that once evils are dispelled then the right qi recovers, and “ clearing the stomach and the intestine by removing old feed grass, promoting ying qi and defensive qi by discharging concretions and conglomerations, thus genuine reinforcement can be realized without actual reinforcement” (陈莝去而肠胃洁，癥瘕尽而营卫昌，不补之中有真补存焉) cited from the Confucians’ Duties to Their Parents ( Rú Mén Shì Qīn , 儒门事亲), which raises the purgative function to the level of promoting the flow of qi and blood and achieving the new by acknowledging the old, thus broadening the indications of the purgative method and enriching the treatment content of syndrome differentiation and treatment in purgative formulas. In the Ming and Qing Dynasties, descending and purgative formulas achieved great advancement in the practice of treating warm pathogenic diseases. This is exemplified by the work of Wu You-xing, a medical expert in warm pathogenic diseases during the Ming Dynasty, who held that the evil qi in all types of channels could enter the gastro-intestines to form an excess in the yangming fu organs, and once the evil qi enters the gastro-intestines, purgative formulas could be used for treatment. Additionally, he proposed original theories such as: “ It is crucial to dispel exogenous evils early, ” (客邪贵乎早逐) “ It can never be too early to purge in warm pathogenic diseases, ”(温病下不厌早) and: “ Never detain constipated feces. ” (勿拘结粪), cited from Discussion on Warm Epidemics ( Wēn Yì Lùn , 温疫论) Ye Gui and Wu Tang, masters in the treatment of warm pathogenic diseases during the Qing Dynasty, were skilled in the application of purgative formulas, and established treatment methods for warm pathogenic diseases such as retaining yin in emergent purgation and supplementing fluid. In the Systematic Discussion on Warm Pathogen Diseases , six types of Chéng Qì Tāng (Qi-Coordinating Decoctions) formulas, i. e. Hù Wèi Chéng Qì Tāng (Stomach-Protecting Qi-Coordinating Decoction, 护胃承气汤), Zēng Yè Chéng Qì Tāng (Humor-Increasing Qi-Coordinating Decoction, 增液承气汤), Niú Huáng Chéng Qì Tāng (Bovine Bezoar Qi-Coordinating Decoction, 牛黄承气汤), Dăo Chì Chéng Qì Tāng (Red-Abducting Qi-Coordinating Decoction, 导赤承气汤), Xuān Bái Chéng Qì Tāng (White-Diffusing Qi-Coordinating Decoction, 宣白承气汤), Táo Rén Chéng Qì Tāng (Peach Kernel Qi-Coordinating Decoction, 桃仁承气汤) are presented for various syndromes of warm pathogenic diseases, thus broadening the field of application for purgative formulas in the treatment of warm pathogenic diseases. Since the founding of the People's Republic of China, great advancement has been attained in the clinical and experimental research of purgative formulas. Good efficacy has been achieved in the treatment of acute infectious diseases such as epidemic cerebrospinal meningitis, encephalitis B, epidemic hemorrhagic fever, bacillary dysentery, pneumonia, ileotyphus and viral hepatitis. Relief of symptoms and improvement in prognosis have also been achieved in the treatment of acute advanced diseases such as exudative pleurisy, abdominal dropsy from hepatic cirrhosis, hepatic encephalopathy, pulmonary encephalopathy and acute renal failure, thus opening up new paths for treatment methods. Particularly in the researching process of acute abdominal disorders, the application of purgative formulas has been extended wider by breaking through conventional thoughts on cautious use of purgatives in biomedicine. A flood of new formulas represented by Fù Fāng Dà Chéng Qì Tāng (Compound Formula Major Qi-Coordinating Decoctions, 复方大承气汤), Lán Wĕi Qīng Huà Tāng (Appendix-Clearing and Resolving Decoction, 阑尾清化汤), Lán Wĕi Qīng Jiĕ Tāng (Appendix-Clearing and Resolving Decoction, 阑尾清解汤), Fù Fāng Dà Chái Hú Tāng (Compound Formula Major Bupleurum Decoction, 复方大柴胡汤), Qīng Yí Tāng (Pancreas-Clearing Decoction, 清胰汤), Dăn Dào Pái Shí Tāng (Biliary Calculus Decoction, 胆道排石汤) indicate that purgative formulas have developed to a new stage, which is drawing close interest from the medical and pharmaceutical fields both domestically and abroad.

The purgative formulas have a wide range of indications such as interior excess syndromes, stagnation of blood stasis, interior blockage of water retention, calculus, parasitic accumulation, and the stomach-intestinal excess accumulation and obstruction of fu qi. It was indicated by Zhang Cong-zheng that: “ All the purgative treatments such as that of hastening child birth, promoting lactation, breaking down accumulations, purging of body fluids, opening up of menstruation and discharging of qi can be achieved ” (催生，下乳，磨积，逐水，破经，泄气，凡在下者皆可下), cited from the Confucians’ Duties to Their Parents . Thus, purgative formulas have a much wider range of application than only that of laxatives. There are many kinds of classifications of purgative formulas. However, for the purpose of comprehensive research on the principle, they can be mainly divided into two types, i. e. cold precipitation and warm precipitation, according to the different cold and warm properties. As for other types such as drastic purgation, relaxing purgation, lubricating purgation, fluid-purging exercises and simultaneous application of purging-tonifying therapy, these are the variant therapies due to the differences between drastic and relaxing efficacies, various pathogens, and strong or weak constitutions, and can be classed into cold purgation and warm purgation respectively according to the differences between the properties of cold and warmth.