Introduction: Mr. Jiang Erxun's experience and principles in using Xiao Chai Hu Tang to treat external infections in debilitated individuals.

Veteran Traditional Chinese Medicine practitioner Jiang Erxun, with over fifty years of clinical experience, consistently adheres to the principles and methods of Zhang Zhongjing as his standard. He is skilled in using Xiao Chai Hu Tang to treat common cold in debilitated individuals.

Here, we briefly summarize his unique clinical experience, and we welcome corrections from fellow practitioners for any inaccuracies.

Mr. Jiang pointed out that since the Han and Tang dynasties, medical texts discussing the treatment of colds in individuals with deficient constitutions have generally focused on identifying whether the deficiency lies in qi, blood, or yin. Based on this assessment, formulas such as those for supplementing qi and releasing the exterior, nourishing blood and releasing the exterior, nourishing yin and releasing the exterior, or supporting yang and releasing the exterior are applied accordingly. If the diagnosis is accurate and the formula is precisely tailored, it can naturally yield effective results.

However, because the ratio of exterior-releasing herbs to qi-tonifying herbs is difficult to master, even a slight misstep can lead to either excessive dispersion or trapping pathogens inside, inevitably violating the principle of "treating deficiency as excess or excess as deficiency."

In contrast, using Xiao Chai Hu Tang (Minor Bupleurum Decoction) to treat colds in individuals with deficient constitutions—including those with sores, nosebleeds, excessive sweating, urinary issues, postpartum conditions, and other cases where there are exterior symptoms but sweating should not be induced—is not only safe and appropriate, avoiding the aforementioned pitfalls, but also remarkably simplifies the treatment process, making it easy to apply with proficiency.

The specific usage is as follows:

For cases of "deficiency constitution cold" treated with Xiao Chai Hu Tang, in addition to strictly following the seven types of possible symptom modifications in the original formula, there are four commonly used modifications:

For qi deficiency, add Astragalus and Atractylodes; for blood deficiency, add Angelica sinensis and white peony root; for yin deficiency, remove Pinellia and appropriately add Polygonatum odoratum and Rehmannia; for yang deficiency, remove Scutellaria and appropriately add processed aconite and Morinda officinalis.

Now, two proven cases are presented to illustrate this:

Case 1: Zhang, female, 45 years old, residing at Zhuangyuan Street, Emei County.

She had long suffered from metrorrhagia and metrostaxis, resulting in deficiency of qi and blood. One day, she was suddenly caught in a fire and went outside, exposing herself to wind. She became bedridden and sought medical treatment for over two months, but her condition worsened daily.

It was midsummer. I drove to welcome Dr. Jiang, arriving at her home at noon. I saw her lying in a small room with tightly closed windows and heavy curtains drawn.

She had aversion to wind, spontaneous sweating, dizziness, palpitations, nausea, vomiting, and loss of appetite. Her tongue coating was thin and white, and her pulse was wiry, thin, rapid, and weak.

Reviewing the previously prescribed formulas, most were variations of Buzhong Yiqi Tang (Center-Supplementing Qi-Boosting Decoction) and Guipi Tang (Spleen-Restoring Decoction). Dr. Jiang diagnosed it as a common cold with both qi and blood deficiency and prescribed Xiaochaihu Tang (Minor Bupleurum Decoction) with added Huangqi (Astragalus), Baizhu (Atractylodes), Fuling (Poria), and Danggui (Chinese Angelica). After taking one dose, sweating decreased, fever subsided, and all symptoms alleviated.

Adhering to the same formula for another dose, sweating stopped, and the patient felt hungry and asked for food. Subsequently, qi and blood were regulated and supplemented, and recovery was achieved within ten days.

Case 2: Luo, male, 66 years old, from Jiajiang.

He had a long-standing phlegm-fluid retention condition, which frequently recurred and lingered with each winter and spring season. In February 1981, he contracted an external pathogen again, presenting with fever, chills, cough, wheezing, and copious clear phlegm. He had previously taken eight doses of Xiaoqinglong Tang (Minor Green Dragon Decoction, with added Dangshen) and Shensu Yin (Ginseng and Perilla Beverage), among other formulas aimed at dispelling pathogens and supporting the healthy qi. Although his condition improved temporarily, it would relapse immediately upon any exposure to wind-cold, persisting for over a month.

During Dr. Jiang's consultation, the patient still experienced mild aversion to wind and cold, with coughing and wheezing worsening at night, copious phlegm, nausea and vomiting, chest tightness, poor appetite, cold pain in the lower back, cold hands and feet, a white and slippery tongue coating, and a wiry and tight pulse.

It was diagnosed as a cold with cough and wheezing due to yang deficiency. The treatment prescribed was Minor Bupleurum Decoction with the addition of prepared aconite, Hangzhou morinda root, cinnamon twig, dried ginger, and schisandra (removing scutellaria from the original formula).

After taking two doses, the aversion to wind and cold subsided, the hands and feet became warm, and the cold pain in the lower back, coughing, and wheezing all improved.

After removing cinnamon twig from the above formula and continuing with two more doses, all symptoms gradually subsided, except for occasional coughing, reduced appetite, dizziness, and fatigue. The treatment was then switched to Xiangsha Liujunzi Decoction with the addition of astragalus and saposhnikovia to complete the recovery. A follow-up after two months showed no recurrence.

Jiang Lao has been using Xiao Chai Hu Tang to treat colds in debilitated individuals for many years, and it has consistently proven effective. However, he has frequently encountered numerous questions and doubts from both medical practitioners and patients. Below are the key points compiled from Jiang Lao's explanations to address these doubts:

Question 1:

It is commonly said that Xiao Chai Hu Tang is a specific formula for treating Shaoyang syndrome in cold damage disorders. Why can it be used to treat colds in debilitated individuals?

Answer:

Clause 97 of the "Treatise on Cold Damage" states, "When blood is weak and qi is exhausted, the interstices open, and pathogenic qi enters, contending with the righteous qi." This does not solely refer to the etiology and pathogenesis of Shaoyang disease but rather provides a general discussion of the etiology and pathogenesis of external contraction in individuals with deficiency.

In treating this pattern, one must not induce sweating, as it may deplete the qi, blood, yin, and yang of the deficient individual, thereby exacerbating the deficiency.

Zhang Zhongjing formulated Xiao Chaihu Tang to harmonize and resolve it. In the formula, Bupleurum, Scutellaria, and Pinellia work to regulate the pivot mechanism of Shaoyang to reach the qi of Taiyang; Ginseng, Licorice, Jujube, and Ginger assist the middle burner's spleen-earth to guide the pathogen outward. Within its safe and balanced nature, it possesses great power to support the righteous and expel the pathogen. It is truly an excellent formula for treating colds in individuals with deficiency.

Second question:

It is said that Bupleurum has the drawback of "dispersing and raising yang while depleting yin," so how can it treat colds in debilitated individuals and those with fluid or blood depletion?

The *Shennong Bencao Jing* states that Bupleurum primarily treats "cold and heat pathogenic factors" and does not mention any dispersing effect.

Zhang Zhongjing said, "The Shaoyang channel should not be treated with diaphoresis; if diaphoresis is applied, delirium may occur," which reflects the concern that diaphoresis may deplete body fluids and lead to the progression of the disease to the Yangming stage. He also said, "If a Taiyang disease does not resolve and progresses to Shaoyang... treat with Minor Bupleurum Decoction."

Since Zhang Zhongjing prescribed Minor Bupleurum Decoction for Shaoyang syndrome where sweating is contraindicated, it is evident that this formula is not actually a dispersing agent.

As for the question of whether Bupleurum can "raise yang and deplete yin," there has been controversy both in ancient and modern times, which warrants further research.

However, it must be understood that the opportunity to treat diseases with Bupleurum alone is extremely rare, especially when there is hyperactivity of yang and deficiency of yin. It is unheard of to rely solely on Bupleurum while abandoning other herbs. Moreover, the efficacy of Bupleurum and Minor Bupleurum Decoction is not equivalent.

Zhang Zhongjing revealed that the effect of Minor Bupleurum Decoction is to "unblock the upper jiao, allow body fluids to descend, and harmonize stomach qi." How could there be the drawback of "raising yang and plundering yin"?

Third question:

At the onset of a cold, most cases fall within the scope of Taiyang disease. How do you know that all colds in debilitated individuals involve pathogens in the Shaoyang stage and should be treated with Minor Bupleurum Decoction?

There are cases of "deficiency constitution colds" that belong to the Shaoyang pattern, and there are those that do not.

However, Xiaochaihu Decoction originates from the "Treatise on Cold Damage" in the section on Taiyang disease. Apart from the sections on Taiyin disease and Shaoyin disease, this formula is mentioned in the treatment of conditions in all other sections, indicating that it is not exclusively for Shaoyang disease. In fact, it is a formula that regulates the pivot of Shaoyang to facilitate the flow of Taiyang qi.

Moreover, Zhang Zhongjing explicitly stated, "When blood is weak and qi is exhausted, the interstices open, allowing pathogenic factors to enter and contend with the righteous qi."

The interstices are associated with the Shaoyang region. In individuals with weak constitutions, defensive qi is insufficient to consolidate the exterior, allowing external pathogens to directly invade the interstices. Therefore, for individuals with weak constitutions who catch a cold, regardless of whether the pathogenic factors have lodged in Shaoyang, this formula can be used to regulate the pivot of Shaoyang, support the righteous qi, and expel the pathogens lingering in the interstices.

This approach to treatment is more profound compared to later medical texts that discuss treating colds in individuals with weak constitutions, which often rigidly focus on nourishing yin, supporting yang, supplementing qi, or nourishing blood.

Question Four:

In Xiaochaihu Decoction, Pinellia is warm and drying, while Scutellaria is bitter and cold, both unsuitable for conditions of fluid depletion and blood exhaustion. How then can it be used for those who have lost fluids and blood and are re-infected by external pathogens?

The action of a compound formula is not merely the mechanical sum of the effects of its individual herbs. Moreover, Zhang Zhongjing’s principles and applications of formulas are always flexible and dynamic.

Observing the seven modifications listed after the Xiaochaihu Decoction formula, I have supplemented four more. Yet, what is seen in clinical practice far exceeds these.

Moreover, the formula contains the herb Ginseng, which holds profound significance. *Shennong Bencao Jing* states, "Ginseng tastes sweet, slightly cold and non-toxic, primarily tonifying the five viscera..."

Chen Xiuyuan's annotation states: "It primarily tonifies the five zang organs because the five zang organs belong to yin... Now, with the assistance of sweet and cold properties, the five zang organs achieve effects of calming, stabilizing, stopping, clarifying, opening, and benefiting. Therefore, Zhang Zhongjing used it to rescue body fluids in cases where sweating, vomiting, or purging had damaged yin."

Xiao Chaihu Tang uses ginseng combined with licorice, jujube, and ginger to support the qi of the middle jiao and spleen-earth, nourish the source of sweat, and serve as the foundation for overcoming pathogenic factors. This allows other herbs with biased properties to leverage their strengths while avoiding their weaknesses, making it a well-regulated formula that is invincible in battle.