Discussion on the Decoction Method of Zhang Zhongjing’s Formulas
Department of Traditional Chinese Medicine, Shaanxi University of Traditional Chinese Medicine, Yang Wanzhang
Having a sharp blade is not enough; without refined techniques, one cannot prevail. A physician must not only differentiate diseases and recognize patterns but also be cautious in prescribing formulas and medications. This includes the selection of dosage forms and the methods of decoction and administration, which are all significant areas of study. Observing over three hundred formulas in Zhang Zhongjing’s “Shang Han Lun” and “Jin Gui Yao Lue”, they are not only precise in theory and method but also rigorous in formulation, and the “physician’s advice” at the end of each formula shows considerable thought. Zhang Zhongjing pioneered the study of formulas, with diverse dosage forms, detailed preparations, and rich methods of use, greatly influencing later generations. Many effective methods are still widely used today and have seen new developments. The author will summarize and elaborate on the decoction methods of Zhang Zhongjing’s formulas; any inaccuracies are respectfully invited to be corrected.
Decoctions are the main dosage form of Zhang Zhongjing’s formulas. “Tang” means to wash away. It is chosen for its rapid efficacy, used for more severe diseases, and can adapt to changes in the condition for differential treatment.
1. Decoction Methods
1. Processing of Medicinal Ingredients: The processing of medicinal ingredients involves pharmaceutical issues. In Zhang Zhongjing’s era, medicine and pharmacy were integrated, so most practitioners mastered the preparation and processing methods of medicinal substances. Here, we will summarize the special processing of medicinal ingredients during decoction.
(1) Processing of Medicinal Ingredients: For example, slicing ginger, splitting jujubes, peeling apricot kernels, removing the skin and breaking Aconite into eight pieces, and removing the heart of Ophiopogon.
(2) Honey Processing: For example, for the bird’s head, boil three liters of water to extract one liter, then add two liters of honey and boil until the water vapor evaporates, then take the medicine. This is to control the toxicity of the bird’s head while retaining its therapeutic effect.
(3) Bag Decoction: For substances like Talc, Daizhe Stone, and Fragrant Beans, they are wrapped in cotton to prevent the decoction from becoming turbid, making it difficult to take. This is especially important for patients who are prone to vomiting.
(4) Pre-decoction: This means adding the medicinal ingredients first. The purpose is to eliminate side effects. For example, pre-decocting Ephedra and Pueraria to remove foam can reduce side effects like restlessness or nausea; it also ensures that the medicinal properties are fully extracted, especially for heavy or toxic substances. For instance, in the formula for Suan Zao Ren (Sour Jujube Seed), the Suan Zao Ren is added later, and in the formula for Gui Zhi (Cinnamon Twig) with Shao Yao (Peony), the Shu Qi (Shuqi) is added later.
(5) Post-decoction: This has several meanings. One is to reduce the volatility of effective components, such as adding Gui Zhi later in the Gui Zhi Ren Shen Tang (Cinnamon Twig and Ginseng Decoction) to preserve its warming and exterior-releasing effects; another is to enhance therapeutic effects based on treatment needs and the properties of the medicinal ingredients.
(6) Others: For example, Ejiao (Donkey-hide Gelatin) should be melted; in the Jiao Ai Tang (Mugwort and Donkey-hide Gelatin Decoction), Mang Xiao (Mirabilite) is often dissolved with low heat, such as in the Tiao Wei Cheng Qi Tang (Regulate the Stomach and Order the Qi Decoction); egg yolk should be added to the decoction after it cools slightly, mixed well, and then boiled to a paste; pig bile and human urine are added to the decoction after it is prepared.
2. Selection of Decoction Liquids: Mainly water, but also “Gan Lan Shui” (Sweet Dew Water), “Liao Shui” (Drain Water), “Dong Liu Shui” (East Flowing Water), “Quan Shui” (Spring Water), etc. Their role may be to ensure cleanliness or to adapt to local conditions. The differences in the components and therapeutic effects of various waters still require further research; in any case, the goal is to promote the effective components of the medicinal ingredients to be fully extracted.
Other liquids include clear rice water, wine, bitter wine, honey, pig fat, and horse urine. One can serve as a solvent, and the other can provide therapeutic effects.
Clear rice water: According to Wu Yiluo, “also known as sour rice water, it is made by soaking cooked chestnut rice in cold water for five or six days, resulting in a sour taste and a milky color, hence the name. Bitter soaking can harm people, its nature is cool and good at moving, can regulate the middle, promote qi, open the stomach, relieve thirst, and transform stagnation.” Formulas like Zhi Shi Zhi Zi Chi Tang (Bitter Orange and Gardenia Decoction) utilize this.
Wine: Zhang Zhongjing used rice wine. Many formulas combine wine and water for decoction, such as Dang Gui Si Ni Tang (Angelica Decoction) with Wu Zhu Yu (Evodia) and Sheng Jiang (Fresh Ginger), to harmonize qi and blood, open the meridians, or guide the medicine to the affected area.
Bitter wine, i.e., vinegar, is used in decoction or alone, such as in Qi Shao Gui Jiu Tang (Astragalus and Peony Decoction) and Bitter Wine Decoction, which can guide the medicine into the nutrient level and drain heat and dampness.
Honey, when used in decoction, or added after the decoction, mainly serves to control the toxicity of certain medicines, such as Wu Tou Tang (Aconite Decoction) and Gan Sui Ban Xia Tang (Kansui and Pinellia Decoction), or to nourish the middle, such as in Gan Cao Fen Mi Tang (Licorice Powder and Honey Decoction).
Other substances like pig fat are used for their lubricating and guiding effects. Horse urine has a downward guiding effect on blood, but is rarely used now, often replaced by children’s urine.
3. Amount of Decoction Liquid Added: The main liquid used for decoction is water, which Zhang Zhongjing did not specify in detail. However, reviewing the formulas in “Shang Han” and “Jin Gui”, the amount of water is generally determined by the quantity of medicinal ingredients, the urgency of the illness, and the required decoction time. Generally speaking, if the medicine needs to be pre-decocted or concentrated, or if there are many ingredients, the water can be as much as one dou (approximately 10 liters) or more. For example, in Xiao Chai Hu Tang (Minor Bupleurum Decoction) and Ma Huang Sheng Ma Tang (Ephedra and Cimicifuga Decoction). If the decoction time is short, and the number of ingredients is few, the water added is only three to five liters. Additionally, if the medicine needs to be taken in one dose or divided into two doses, the amount of water added is less, such as in Gui Zhi Gan Cao Tang (Cinnamon and Licorice Decoction). However, most medicines require five to eight liters of water. For instance, in the Zhi Shi Zhi Zi Tang (Bitter Orange and Gardenia Decoction), seven liters of water is used, and in the Zhi Gan Cao Tang (Honey Licorice Decoction), seven liters of wine and eight liters of water are used for decoction. The rest is added according to therapeutic effects and decoction needs.
4. Decoction Fire Level: Zhang Zhongjing generally did not specify the fire level, only mentioning “gentle fire” when decocting Gui Zhi Tang (Cinnamon Decoction). In Xiao Jian Zhong Tang (Minor Construct the Middle Decoction) with maltose, to avoid burning, it is noted to “use gentle fire to dissolve”; Mang Xiao is boiled with gentle heat until it boils once, such as in Da Cheng Qi Tang (Major Order the Qi Decoction) and Da Huang Mu Dan Pi Tang (Rhubarb and Peony Decoction). The significance is to avoid the volatility of effective components in some medicines, while others are afraid of sticky medicines burning. For those not specified, moderate heat is appropriate.
5. Decoction Time and Frequency: Expelling and purging medicines require a short decoction time, while warming, tonifying, and dispersing cold medicines generally require a longer decoction time. Medicines with strong toxicity also require longer decoction times. Generally, medicines are decocted until half of the added water is reduced. For example, in Ge Gen Tang (Kudzu Decoction), water is used to boil down from one dou to six liters, removing foam, and then adding other ingredients. The decoction yields three liters of medicinal liquid. In Zhen Wu Tang (True Warrior Decoction), eight liters of water is used to yield three liters. Overall, Zhang Zhongjing’s decoction method emphasizes filtering out the medicinal residue after one decoction, thus the decoction time is generally longer. If the medicine does not show effect after taking, and the symptoms persist, another dose may be decocted, or even two or three doses may be taken. This shows that one dose of medicine is generally decocted once, which has the advantage of maintaining equal concentration and efficacy in divided doses. Additionally, Zhang Zhongjing sometimes uses special markers to determine decoction time, such as in Bai Hu Tang (White Tiger Decoction) and Tao Hua Tang (Peach Blossom Decoction), which are based on the cooking of rice.
6. Special Decoction Methods: There are three types.
(1) Separate Decoction: For example, in Fu Zi Xie Xin Tang (Aconite Decoction) and Wu Tou Gui Zhi Tang (Aconite and Cinnamon Decoction). Aconite and the bird’s head require long decoction or special processing, hence the need for separate decoction. In Fu Zi Xie Xin Tang, Aconite is “cooked separately to extract the juice” to restore yang and consolidate the defensive qi, while Da Huang and Huang Qin are soaked in Ma Fei Tang (Ma Fei Decoction) to extract the juice to eliminate phlegm; in Wu Tou Gui Zhi Tang, Aconite is separately decocted with honey, purely to control its toxicity, thus the juice is combined with the juice of the Gui Zhi Tang for administration, which considers the complex condition and allows the medicine to exert different effects.
,(2) Remove Residue and Re-decoct: This method is often used in harmonizing formulas, such as in Xiao Chai Hu Tang, which states, “After the seven ingredients, use one dou and two sheng of water, boil to yield six sheng, remove the residue, and re-decoct to yield three sheng, warm and take one sheng, three times a day.” This is a method of concentrated preparation, which can reduce the dosage and gastrointestinal irritation; the essence of its significance requires further exploration.
(3) Boiling Decoction: For example, in Da Huang Huang Lian Xie Xin Tang (Rhubarb and Coptis Decoction), it uses Ma Fei Tang to soak the medicine briefly, extracting the juice to take advantage of its light and uplifting qi, avoiding the heavy and turbid taste, to clear the upper part of the formless evil heat.
2. Administration Methods
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Dosage: Generally, one dose is about one sheng (approximately 0.5 liters), with a maximum of one sheng and three he (approximately 0.75 liters), and a minimum of two or three he. For non-urgent conditions or mild medicines, the dosage is around one sheng; for severe conditions or potent medicines, start with a small amount and gradually increase to the full dose, “to know as the measure.” Aconite and Wu Tou formulas often follow this method. For example, in Wu Tou Gui Zhi Tang, after obtaining one sheng of decoction, “initially take two he, if unsure, take three he, and if still unsure, increase to five he.” This shows caution in taking toxic substances. Additionally, for patients with vomiting, the dosage should also be small, generally around five he, to prevent vomiting due to large doses, which may hinder efficacy. Furthermore, the dosage should also consider the patient’s constitution and age; for toxic substances, stronger individuals can take more, while weaker individuals should take less, such as in Da Qing Long Jia Shi Gao Tang (Major Blue Dragon Decoction with Gypsum), where “strong individuals take one sheng, weaker individuals reduce it, taking three times a day, and children take four he.”
2. Frequency of Administration: This is determined by the needs of the treatment. Generally, one dose of medicine is divided into three administrations. However, in different conditions, the number of administrations varies, and the significance is different.
Taking in one dose has three meanings: one is for urgent conditions that require rapid relief, such as in Tiao Wei Cheng Qi Tang (Regulate the Stomach and Order the Qi Decoction); the second is for medicines with fewer ingredients, where the decoction yields less liquid, or some medicines need to be concentrated for rapid effect, such as in Ting Li Da Zao Wei Fei Tang (Ting Li and Jujube Decoction); the third is for small amounts of medicine, such as Ban Xia Gan Jiang San (Pinellia and Ginger Powder).
Taking once a day: For potent medicines and severe conditions, frequent administration may not be tolerated, or may easily lead to toxicity, such as in Da Wu Tou Decoction and Shi Zao Tang (Ten Jujube Decoction), emphasizing “do not miss, take again tomorrow, do not take again in one day.”
Taking again during the day and three times a day: This is often used for milder or more balanced medicines, or for those requiring prolonged treatment. This will not be elaborated further.
Taking again at night and three times a day: This is to maintain a certain concentration of the medicine in the body, or for some complex conditions requiring day and night administration, such as in Gui Zhi Ren Shen Tang (Cinnamon and Ginseng Decoction) for warming and exterior-releasing. For treating heat in the chest and cold in the stomach, the Huang Lian Tang (Coptis Decoction) emphasizes taking three times a day and twice at night, with each dose being one sheng, to maintain a certain concentration of the medicine in the body and accelerate the adjustment of mixed cold and heat conditions.
Additionally, Zhang Zhongjing also uses daily life phenomena as markers for intervals between doses. For example, in Da Jian Zhong Tang (Major Construct the Middle Decoction), it states, “Use four liters of water, boil to yield two liters, remove the residue, add one liter of gelatin, and simmer gently to yield one and a half liters, taking warm again, as one meal is completed, drink two bowls of porridge, then take again.” “One meal” refers to the time concept, meaning after taking the medicine, it is approximately the time taken to prepare a meal, drink two bowls of porridge, and then take the medicine again. This indicates the intention of frequent administration.
Moreover, some decoctions are also taken in divided doses. However, to adapt to the needs of the condition, especially to enhance the sustained effect of the medicine, it emphasizes shortening the time between doses. For example, if Gui Zhi Tang does not cure, it is advised to “shorten the interval.” In the case of Ze Qi Tang (Water-Draining Decoction), it states, “Boil to yield five liters, take warm five he until night ends.” Although some mention divided doses, in acute conditions that change rapidly, or when a single dose can cure the disease, it emphasizes, “no need to take the entire dose,” which may be an overcorrection, such as in Da Qing Long Tang and Tao Hua Tang.
3. Timing of Administration: Generally, for two or three times, although not specified when to take, it can be divided into morning, noon, and evening, or morning and evening, or taken day and night. There are two special methods of administration:
Taking on an empty stomach: This emphasizes taking the medicine on an empty stomach. The purpose is to facilitate the full absorption of the medicine; it also allows the medicinal properties to reach the lower jiao (lower abdomen) directly. For example, in the formula for Tao Ren Cheng Qi Tang (Peach Kernel Decoction), it states, “After the five ingredients, use seven liters of water, boil to yield two and a half liters, remove the residue, add Mang Xiao, and take warm on an empty stomach five he, three times a day, should have a slight purgative effect.”
Taking at dawn: This is only emphasized in the Shi Zao Tang. In the formula, Gan Sui, Da Ji, and Yuan Hua are strong purgatives, and diuretic agents can easily harm yang qi. Therefore, it is advised to take the jujube soup at dawn with a small amount of medicine, and if there is a significant purgative effect, drink hot porridge immediately. If the condition does not improve, do not take the medicine again, but increase the dose the next day. This shows that taking medicine at dawn, when yang is strong, may be beneficial for expelling water and dampness, indicating Zhang Zhongjing’s meticulousness.
4. Auxiliary Measures for Administration: After taking the medicine, although it matches the symptoms, if the condition is severe, it may be difficult to exert its effects immediately, or some medicines may harm the righteous qi while expelling the evil, thus requiring some auxiliary measures. For example, for exterior-releasing and cold-dispelling medicines, it is often emphasized to cover oneself with a cotton quilt after taking the medicine, or to drink one or two bowls of hot thin porridge, such as in Gui Zhi Tang, which primarily releases the exterior. This can assist the medicinal power, nourish the source of sweat, and facilitate the expulsion of evil through sweating; similarly, in Li Zhong Tang (Regulate the Middle Decoction), to warm and disperse cold in the middle jiao, it emphasizes, “After taking the decoction, if feeling cold, drink about one liter of hot porridge, slightly warm, do not uncover the quilt,” aiming to accelerate the warming and dispersing of cold evil.
5. Contraindications for Administration: For example, when taking exterior-releasing medicines, one should “not allow water to flow freely.” Excessive sweating can lead to excessive leakage, making it difficult to expel the evil, and may even lead to deeper invasion. Secondly, dietary restrictions are necessary; all raw, cold, slippery, meaty, alcoholic, and foul-smelling foods should be avoided or minimized. Thirdly, one should avoid wind and cold, as during sweating, the pores are open, making it easy for wind and cold evils to invade the body again.
Additionally, patients with vomiting should not use Jian Zhong Tang; those who consume alcohol should not use Gui Zhi Tang; postpartum women and the weak should take Aconite formulas sparingly; and those with blood deficiency should not use purgatives.
6. Judging and Handling Abnormal Situations After Taking Medicine.
(1) Aconite and Wu Tou formulas are quite potent, and after the disease mechanism, there are often symptoms of dizziness. According to the “Shang Shu: Shuo Ming Shang”, it states, “If the medicine does not cause dizziness, the disease will not heal.” Therefore, dizziness is often a normal phenomenon; if there are no other discomforts, “do not blame it.” At this time, the physician should be aware and explain clearly to the patient to alleviate concerns; generally, it can continue to be taken, but for caution, the dosage should be reduced. Just as in the formula for Qu Gui Jia Shu Tang, it states, “Three pieces of Aconite may be too much; for the weak and postpartum women, reduce the dosage directly.”
(2) After taking diaphoretic medicines, if sweating excessively, it is advisable to use warm powder, and it may be necessary to stop the medicine.
(3) For Ba Dou formulas, if there is no purgation, it is advisable to take a cup of hot porridge; if purgation does not stop, it is advisable to take a cup of cold porridge. Why is this so? Because Ba Dou is very pungent and hot, it can cause vomiting and purgation. If there is no purgation, it may not be due to the medicine not working, but rather due to excessive cold blocking, preventing the hot medicine from working, or the dosage being insufficient to cause purgation. Therefore, drinking hot porridge can enhance heat and promote the medicinal effect; if purgation does not stop, it is due to the medicine causing heat purgation, and drinking cold porridge can restrain the condition, stopping the purgation.
(4) Some decoctions may cause feelings of restlessness after taking. The reasons may vary, including individual differences, the influence of certain medicines, or expected reactions. In any case, if the restlessness is mild, and after repeated verification, the formula matches the symptoms, it can be taken again until sweating occurs, such as in Chai Gui Gan Jiang Tang (Chai Hu, Cinnamon, and Ginger Decoction). If the restlessness persists without relief, other measures can be taken, such as needling Feng Tai and Feng Fu before taking Gui Zhi Tang again.
7. The Significance of Different Preparations and Decoction Methods for Repeated Formulas
(1) For the same type of disease, the administration method varies according to severity. For example, in Tiao Wei Cheng Qi Tang, if the Tai Yang condition is mismanaged, leading to the use of warming agents to restore yang, resulting in disharmony of stomach qi and delirium, due to the not-so-severe blockage in the intestines, it is necessary to harmonize the stomach qi to relieve discomfort. The formula states, “Take a small amount warm,” indicating to take in small divided doses to avoid severe purgation.
Conversely, if the Tai Yang disease is mismanaged, leading to the depletion of body fluids, the exterior condition dissipates, and it transitions into Yang Ming, causing dryness and blockage, or if the Yang Ming disease has not been purged and the patient experiences restlessness, heat, fullness, and constipation, the condition is more urgent, requiring purgation to clear heat and harmonize stomach qi, thus the original formula is taken “warm and in large doses” to quickly relieve suffering.
(2) Different diseases with the same formula have different decoction methods.
For example, in Da Huang Huang Lian Xie Xin Tang, the “Shang Han Lun” uses it to treat “stagnation under the heart, soft and painless upon pressing.” Although the heat is intense, it has not combined with tangible substances, thus only the stagnation under the heart is observed, and it is emphasized to use Ma Fei Tang to soak the medicine for a while, extracting the juice for administration. The significance lies in its light and uplifting qi, avoiding the heavy and turbid taste to clear the upper part of the formless evil heat.
In contrast, in the “Jin Gui: Palpitations, Vomiting, and Hemorrhage” section, it is used to treat “insufficient heart qi, leading to vomiting and bleeding.” Due to the strong fire consuming qi, the heat invades the yang channel, causing blood to overflow. Therefore, it states, “Use three liters of water, boil to yield one liter, and take in one dose.” This utilizes the bitter and cold purging effect to reduce the heat, stopping the vomiting and bleeding.
(3) For the same disease with the same formula, the preparations and administration methods differ. For example, in the “Shang Han Lun” section 386, for cholera with vomiting and diarrhea, headache, and body pain, with significant cold, and unwillingness to drink water, the method is to use warming to disperse cold, strengthen the spleen, and tonify the middle with Li Zhong Wan (Regulate the Middle Pill). Generally, pills are convenient to take, and frequent administration yields quick results. However, since “pills are slow,” if the cold evil is significant, pills cannot achieve rapid effects, thus it states, “but not as effective as decoctions,” as decoctions act more rapidly. Additionally, after taking the medicine, drinking hot thin porridge, and emphasizing “do not uncover the quilt,” all strengthen the warming and dispersing of cold, ensuring rapid recovery.
Conclusion
The administration methods of Zhang Zhongjing’s formulas can be seen from the above. Decoctions have been a major dosage form in the practical application of Traditional Chinese Medicine from ancient times to the present. The decoction methods of Zhang Zhongjing’s formulas closely adhere to the principles of differential diagnosis and treatment, with rigorous and measured application, having a profound impact on later generations and being carried forward by physicians throughout history.
The methods of decocting and administering medicines, although they pertain to pharmaceutical science and nursing knowledge, are an important aspect of clinical practice in Traditional Chinese Medicine. As clinical practitioners, it is essential to study and master these contents to improve efficacy and serve the health of the people.
(This article is dedicated to Professor Du Yuma and Teacher Wang Jinghong for their guidance)
Source: Shaanxi Traditional Chinese Medicine Correspondence Journal, 1983, Issue 1, published by Shaanxi University of Traditional Chinese Medicine