1. Prescription Source and History

1. Origin Background

The Dingchuan Decoction was first recorded in the book *The Marvelous Recipes for Health Preservation* written by Zhang Shiche, a medical expert in the Ming Dynasty. In ancient times, asthma was a relatively common disease that severely affected people's quality of life. Due to limited medical conditions at that time, there was a lack of systematic and effective treatment methods for asthma. Through long-term clinical practice, Zhang Shiche continuously summarized experience, collected and improved folk remedies, and finally created the Dingchuan Decoction. Its emergence brought new hope to numerous asthma patients and had important pioneering significance in the field of traditional Chinese medicine for treating asthma.

2. Historical Heritage

Since the advent of the Dingchuan Decoction, it has been widely spread in the field of traditional Chinese medicine. Physicians of all generations have attached great importance to it and continuously verified and improved it in clinical applications. Over time, it has been included in numerous traditional Chinese medicine classics and has become one of the classic prescriptions for treating asthma in traditional Chinese medicine. Different physicians have made some expansions and refinements to the use of the prescription based on their clinical experience, making its curative effect in treating asthma more precise. For example, there are some subtle changes in aspects such as the adjustment of the dosage and the processing methods of the herbs, all of which are to better adapt to the conditions and constitutions of different patients. It is not only widely used in China but also has had a certain impact on the development of traditional Chinese medicine in neighboring countries and regions, becoming a bright name card for traditional Chinese medicine in treating respiratory diseases.

2. Composition of Medicinal Flavors

1. Monarch Drugs - Ephedra and Ginkgo Seeds

- **Ephedra**: Ephedra is one of the monarch drugs in the Dingchuan Decoction. It is pungent, slightly bitter, and warm in nature. It belongs to the lung and bladder meridians. Ephedra has the effects of inducing sweating and relieving exterior syndrome, dispersing lung qi to relieve asthma, and promoting diuresis to alleviate edema. In the Dingchuan Decoction, Ephedra mainly plays the role of dispersing lung qi to relieve asthma. It can open and disperse the lung qi, enabling the lung qi to be dispersed and the airway to be unobstructed, thereby relieving asthma symptoms. The sweating effect of Ephedra can expel exogenous pathogenic factors through sweating, and it has a good therapeutic effect on asthma caused by exogenous wind-cold. Its strong pungent-dispersing power can quickly disperse the cold pathogen in the lung and restore the normal function of the lung.

- **Ginkgo Seed**: Ginkgo Seed is sweet, bitter, and astringent in taste, neutral in nature, and slightly toxic. It belongs to the lung meridian. Ginkgo Seed has the effects of astringing the lung to relieve asthma, arresting vaginal discharge, and reducing urination. In the Dingchuan Decoction, it is combined with Ephedra, one dispersing and one astringing. Ephedra disperses lung qi to relieve asthma, while Ginkgo Seed astringes the lung to relieve asthma. The two restrict and synergize with each other. The excessive dispersion of Ephedra may consume the lung qi, and the astringency of Ginkgo Seed can prevent the excessive dissipation of the lung qi. At the same time, it can enhance the power of relieving asthma, enabling the dispersion and descent of the lung qi to reach a balance, thus better treating asthma.

2. Minister Drugs - Apricot Seeds and Tussilago

- **Apricot Kernel**: Apricot Kernel is bitter and slightly warm in nature. It belongs to the lung and large intestine meridians. Apricot Kernel has the effects of lowering qi to relieve cough and asthma and moistening the intestine to promote defecation. In the Dingchuan Decoction, Apricot Kernel mainly plays the role of lowering qi to relieve asthma. It can lower the lung qi, enabling the rebellious lung qi to descend and be purified. In combination with the lung-dispersing effect of Ephedra, one dispersing and one descending, it adjusts the qi movement of the lung and relieves the symptom of rapid breathing during asthma. The bitter-lowering property of Apricot Kernel can also resolve phlegm, helping to eliminate the phlegm in the lung and relieve airway obstruction.

- **Tussilago farfara**: Tussilago farfara is pungent, slightly bitter, and warm in nature. It belongs to the lung meridian. Tussilago farfara has the effects of moistening the lung and lowering qi, relieving cough and resolving phlegm. It can warm and moisten the lung and has a good therapeutic effect on cough and asthma due to lung cold. In the Dingchuan Decoction, Tussilago farfara synergizes with Apricot Kernel to enhance the effect of relieving cough and asthma. The lung-moistening effect of Tussilago farfara can relieve lung dryness, and its phlegm-resolving power can make the phlegm easier to expectorate, further alleviating asthma symptoms.

3. Assistant Drugs - Pinellia, Mulberry Bark and Scutellaria

- **Pinellia ternata**: Pinellia ternata is pungent, warm in nature, and slightly toxic. It belongs to the spleen, stomach, and lung meridians. Pinellia ternata has the effects of drying dampness and resolving phlegm, lowering adverse qi to arrest vomiting, and dissipating binds and nodules. In the Dingchuan Decoction, Pinellia ternata mainly plays the role of drying dampness and resolving phlegm. Asthma patients often have symptoms of excessive phlegm. Pinellia ternata can dry dampness and resolve phlegm, reducing the amount of phlegm, thereby relieving airway obstruction and asthma. Its effect of lowering adverse qi to arrest vomiting also helps to relieve discomfort symptoms such as nausea and vomiting caused by asthma.

- **Mulberry Bark**: Mulberry Bark is sweet and cold in nature. It belongs to the lung meridian. Mulberry Bark has the effects of purging the lung to relieve asthma and promoting diuresis to alleviate edema. In the Dingchuan Decoction, Mulberry Bark can clear away lung fire, relieve asthma and cough. It can clear the lung heat, and has a good therapeutic effect on asthma caused by excessive heat in the lung. The diuretic effect of Mulberry Bark can also expel the excess fluid in the lung, reducing the burden on the lungs and contributing to the recovery of asthma.

- **Scutellaria baicalensis**: Scutellaria baicalensis is bitter in flavor and cold in nature. It acts on the lung, gallbladder, spleen, large intestine, and small intestine meridians. It has the effects of clearing heat and drying dampness, purging fire and detoxifying, stopping bleeding, and preventing miscarriage. In Dingchuan Decoction, Scutellaria baicalensis mainly plays the role of clearing heat and resolving phlegm. It can clear the lung fire, resolve phlegm and relieve cough, and cooperate with Morus alba root bark to enhance the power of clearing heat and resolving phlegm. The bitter and cold nature of Scutellaria baicalensis can inhibit the heat pathogen in the lung, reduce the production of phlegm, and has a good therapeutic effect on patients with asthma accompanied by lung heat symptoms.

4. Courier Drug - Licorice Root

Licorice is sweet in flavor and neutral in nature. It acts on the heart, lung, spleen, and stomach meridians. Licorice has the effects of invigorating the spleen and replenishing qi, moistening the lung and relieving cough, clearing heat and detoxifying, and coordinating various herbs. In Dingchuan Decoction, Licorice, as the envoy herb, mainly plays the role of coordinating various herbs. It can coordinate the properties of various herbs in the formula, enabling them to better exert their synergistic effects. The effect of Licorice in moistening the lung and relieving cough can also relieve the cough symptoms during asthma, and its effect of invigorating the spleen and replenishing qi can enhance the patient's constitution, contributing to the recovery of the disease.

III. Pathogenesis, Efficacy and Indications

1. Pathogenesis

The pathogenesis targeted by Dingchuan Decoction is mainly the internal accumulation of phlegm-heat and the external constraint of wind-cold. The lung is in charge of qi and controls respiration. When exogenous wind-cold pathogens invade the lung defense, it causes the lung qi to fail to disperse, the airway to be unsmooth, resulting in symptoms such as cough and asthma. At the same time, there is usually phlegm-heat pathogen in the body. The phlegm-heat accumulates and obstructs the lung, combines with the exogenous pathogen, further aggravating the stagnation of lung qi, thus triggering asthma. This pathogenesis of the mixture of phlegm-heat and wind-cold makes the asthma symptoms relatively complex, with both exterior syndromes such as aversion to cold and fever, and interior syndromes such as cough, asthma, and profuse yellow and thick phlegm.

2. Efficacy

Dingchuan Decoction has the effects of dispersing the lung qi, clearing heat and resolving phlegm, relieving cough and asthma. In the formula, Ephedra and Apricot Seed disperse the lung qi and lower the qi to relieve asthma, Ginkgo Seed astringes the lung to stop asthma. The three cooperate to adjust the qi movement of the lung, making the lung qi disperse and descend normally. Pinellia ternata, Morus alba root bark, and Scutellaria baicalensis clear heat and resolve phlegm, eliminating the phlegm - heat pathogen in the lung. Tussilago farfara and Licorice moisten the lung and relieve cough, and coordinate various herbs. The whole formula works together, which can both disperse wind - cold and clear and purge phlegm - heat, achieving the purpose of relieving cough and asthma.

3. Indications

Dingchuan Decoction is mainly used to treat the syndrome of external constraint of wind-cold and internal accumulation of phlegm-heat. The symptoms include cough and asthma, profuse yellow and thick phlegm, aversion to cold and fever, yellow and greasy tongue coating, and slippery and rapid pulse. Clinically, it is commonly used to treat diseases such as bronchial asthma and asthmatic bronchitis belonging to the above pathogenesis. For patients with asthma during the attack period, especially those with phlegm-heat symptoms, Dingchuan Decoction has a good therapeutic effect. It can quickly relieve the asthma symptoms, reduce discomfort such as cough, asthma, and expectoration, and improve the patient's respiratory function.

IV. Analysis of Formula Principles

1. Compatibility of Dispelling Lung Qi and Lowering Qi

Ephedra disperses the lung qi and relieves asthma, Apricot Seed lowers the qi to relieve asthma. The two, one dispersing and one lowering, cooperate with each other. The dispersing power of Ephedra can open the stagnation of lung qi, enabling the lung qi to be dredged, while the bitter and descending property of Apricot Seed can lower the reversed lung qi and make it descend, restoring the normal ascending and descending of lung qi. This combination of dispersing and descending has a good therapeutic effect on the symptoms of reversed lung qi and airway obstruction during asthma, making the breathing smooth and the asthma relieved.

2. Combination of Dispersing and Astringing

Ephedra and Ginkgo Seed, one dispersing and one astringing. Ephedra disperses wind-cold and opens the lung qi, but its dispersing power is relatively strong and may consume the lung qi. Ginkgo Seed astringes the lung to stop asthma and restrains the lung qi to prevent excessive dispersion of the lung qi. The combination of the two can not only give full play to the role of Ephedra in dispersing the lung qi and relieving asthma, but also avoid excessive consumption of the lung qi, achieving a balance between the dispersion and astringency of the lung qi and better treating asthma.

3. Synergy of Clearing Heat and Resolving Phlegm, Relieving Cough and Wheezing

Morus alba root bark and Scutellaria baicalensis clear heat and purge fire, resolve phlegm and relieve cough, and Pinellia ternata dries dampness and resolves phlegm. They work together to address the pathogenesis of internal accumulation of phlegm-heat. Morus alba root bark and Scutellaria baicalensis clear the lung fire and reduce the production of phlegm-heat, and Pinellia ternata dries dampness and resolves phlegm, making the phlegm easier to expectorate. Tussilago farfara, Apricot Seed, and Licorice relieve cough and asthma, and cooperate with the herbs for clearing heat and resolving phlegm to relieve cough and asthma symptoms, treating asthma from multiple aspects and achieving the effect of treating both the symptoms and the root cause.

V. Comparison with Other Similar Formulas

1. Comparison with Maxing Shigan Decoction

- **Similarities**: Both Maxing Shigan Decoction and Dingchuan Decoction have the effect of dispersing the lung qi and relieving asthma, and can be used to treat asthma and cough. Both contain Ephedra and Apricot Seed. Ephedra disperses the lung qi, and Apricot Seed descends qi, showing similarities in relieving asthma.

- **Differences**: Maxing Shigan Decoction is mainly used to treat the syndrome of exogenous wind pathogen and heat stasis in the lung. Its symptoms are mainly fever and rapid breathing, focusing on clearing heat and dispersing the lung qi. In the formula, the dosage of Gypsum Fibrosum is relatively large to clear the pathogenic heat in the lung. Dingchuan Decoction is mainly used to treat the syndrome of external constraint of wind-cold and internal accumulation of phlegm-heat. In addition to cough and asthma, it is also accompanied by symptoms such as a large amount of yellow and thick phlegm, aversion to cold and fever, focusing on dispersing cold, resolving phlegm and clearing heat. The formula contains phlegm-resolving drugs such as Ginkgo Seed and Pinellia Tuber, as well as heat-clearing drugs such as Scutellaria Baicalensis and Mulberry Bark.

2. Comparison with Suzi Jiangqi Decoction

- **Similarities**: Both have the effect of descending qi and relieving asthma, and can be used to treat asthma and cough.

- **Differences**: Suzi Jiangqi Decoction is mainly used to treat the syndrome of dyspnea and cough due to excess above and deficiency below. Its pathogenesis is the excessive accumulation of phlegm-saliva above and deficiency of kidney yang below. In the formula, Fructus Perillae is used as the monarch drug to descend qi and relieve asthma, combined with Magnolia Officinalis and Peucedanum Praeruptorum to lower qi and resolve phlegm, Cinnamomum Cassia to warm the kidney and receive qi, and Angelica Sinensis to nourish blood and moisten dryness. Dingchuan Decoction is mainly used to treat dyspnea and cough due to internal accumulation of phlegm-heat and external constraint of wind-cold, mainly targeting the pathogenesis of the mixture of phlegm-heat in the lung and exogenous wind-cold, focusing on dispersing the lung qi, descending qi, clearing heat and resolving phlegm.

VI. Clinical Application and Indications

1. Bronchial Asthma

Bronchial asthma is a common chronic airway inflammatory disease. During an attack, it is mostly manifested as symptoms such as wheezing, shortness of breath, chest tightness, and cough. When the patient belongs to the syndrome of external constraint of wind-cold and internal accumulation of phlegm-heat, Dingchuan Decoction has a good curative effect. By dispersing the lung qi, descending qi, clearing heat and resolving phlegm, it can quickly relieve asthma symptoms, reduce airway inflammation, and decrease the frequency of attacks. During clinical application, appropriate additions and subtractions can be made according to the specific symptoms of the patient.

2. Asthmatic Bronchitis

Asthmatic bronchitis also often presents symptoms such as cough, asthma, and expectoration. Its pathogenesis is similar to that targeted by Dingchuan Decoction, which is internal accumulation of phlegm-heat and external constraint of wind-cold. Dingchuan Decoction can improve the symptoms of patients with asthmatic bronchitis, relieve cough and asthma, promote expectoration, and alleviate the condition. During the treatment process, the dosage and composition of the formula are adjusted according to the changes in the patient's condition to achieve the best therapeutic effect.

VII. Modifications of Dingchuan Decoction

1. Severe Cold Pathogen

If the cold pathogen is more severe and the symptoms of aversion to cold and fever are obvious, Ramulus Cinnamomi can be added to enhance the power of dispersing cold and relieving the exterior. Ramulus Cinnamomi is pungent, sweet and warm, can warm and dredge the meridians, assist Ephedra in dispersing wind-cold, so that the exterior pathogen can be better relieved, and relieve the symptoms of aversion to cold and fever during asthma attacks.

2. Excessive Phlegm-Heat

If the phlegm-heat is more severe and the expectoration is yellow, thick and in a large amount, Arisaema Cum Bile and Trichosanthes Kirilowii can be added to enhance the effect of clearing heat and resolving phlegm. Arisaema Cum Bile is bitter, slightly pungent and cool in nature, can clear heat and resolve phlegm, calm wind and stop convulsions. Trichosanthes Kirilowii is sweet, slightly bitter and cold in nature, can clear heat and remove phlegm, widen the chest and disperse stagnation. When the two are added to Dingchuan Decoction, they can further remove the phlegm-heat in the lung and relieve asthma symptoms.

3. Severe Wheezing

For those with more severe wheezing and difficulty breathing, earthworm and semen lepidii can be added to enhance the effect of relieving asthma. Earthworm is salty and cold, belonging to the liver, spleen, and bladder meridians, with the functions of clearing heat and relieving convulsion, dredging collaterals, relieving asthma, and inducing diuresis. Semen lepidii is bitter, pungent, and extremely cold, belonging to the lung and bladder meridians, capable of purging the lung to relieve asthma and promoting diuresis to alleviate edema. They can effectively relieve the symptoms of wheezing and improve respiratory function.

VIII. Dosage (Traditional and Modern Concentrated Granules)

1. Traditional Method

The traditional usage of Dingchuan Decoction is to decoct it for oral administration. Generally, use 9 grams of ephedra, 9 grams of almond, 9 grams of cortex mori, 6 grams of scutellaria baicalensis, 9 grams of pinellia ternata, 6 grams of semen brassicae, 9 grams of flos farfarae, 9 grams of ginkgo seed, and 3 grams of licorice. Add appropriate amount of water to the above-mentioned drugs, soak for a period of time, then boil with strong fire, and then change to slow fire and decoct for about 20 - 30 minutes, take the decoction. One dose per day, taken in two times. This traditional decocting and taking method can fully dissolve the effective components of the drugs and exert the best medicinal effect.

2. Modern Concentrated Granules

With the development of modern technology, Dingchuan Decoction also has a modern concentrated granule dosage form. When using modern concentrated granules, prepare according to the corresponding formula ratio. Generally speaking, the dosage is different from the traditional method and needs to be used according to the instructions of the specific product. Modern concentrated granules have the advantages of convenient taking and easy to carry, suitable for the modern fast-paced lifestyle. Patients only need to take it with boiling water, without the cumbersome decocting process.

IX. Precautions and Taboos

1. Precautions

- Ephedra in Dingchuan Decoction has a strong sweating power. It should be used with caution for those with weak constitution, spontaneous sweating, and night sweating, so as to avoid excessive sweating causing depletion of vital qi.

- Ginkgo seed is poisonous and the dosage should not be too large to avoid poisoning reactions. Generally, the dosage in Dingchuan Decoction is strictly formulated, but patients still need to pay attention to observing their own reactions. If symptoms such as nausea, vomiting, abdominal pain, and diarrhea occur, they should seek medical attention in time.

- During the period of taking the medicine, the diet should be light, avoid eating spicy, greasy, and stimulating foods, so as not to aggravate the pathogenic factor of phlegm-heat in the body and affect the medicinal effect.

2. Taboos

Pregnant women should use Dingchuan Decoction with caution. Because most of the drugs in the formula have the effects of promoting qi and activating blood circulation, resolving phlegm, etc., which may have an adverse impact on the fetus. In addition, those who are allergic to any drug in Dingchuan Decoction are prohibited. The allergic reaction may manifest as rash, itching, difficulty breathing, etc., and in severe cases, it will endanger life. Therefore, once allergic symptoms appear, stop taking the medicine immediately and seek medical attention.

X. Modern Research Progress

1. Pharmacological Research

Dingchuan Decoction is applicable to those with unvented lung qi and internal obstruction of phlegm-heat in asthma syndrome, with the functions of dispersing and descending lung qi, regulating qi and relieving asthma. Clinically, the tongue coating is commonly yellow and greasy.

Modern research shows that the ephedra in Dingchuan Decoction contains components such as ephedrine, which has the effect of relaxing bronchial smooth muscle and can relieve airway spasm during asthma. The amygdalin in almonds has the efficacy of relieving cough and asthma. Drugs such as mulberry bark and scutellaria baicalensis have anti-inflammatory, antibacterial, antiviral and other effects, and can reduce airway inflammation. Pinellia ternata can inhibit the cough center and reduce the frequency of coughing. These drugs work synergistically to jointly exert the therapeutic effect of Dingchuan Decoction.

2. Clinical Research

In recent years, many clinical studies have verified the efficacy of Dingchuan Decoction in the treatment of diseases such as asthma. The research found that Dingchuan Decoction can effectively improve the symptoms of asthma patients, such as reducing cough, asthma, expectoration, etc., and improving the lung function of patients. Compared with some western medicines, Dingchuan Decoction has certain advantages in relieving asthma symptoms, reducing the number of attacks, improving the quality of life of patients, etc., and has relatively few side effects. At the same time, good clinical effects have also been achieved in the treatment of diseases such as asthmatic bronchitis, providing more basis for the clinical application of Dingchuan Decoction.