After two or three days of Taiyang cold damage (Shanghan), if palpitations and irritability occur, Xiao Jian Zhong Tang (Minor Construct the Middle Decoction) is indicated.

After two or three days of Taiyang cold damage, with no Yangming syndrome present, this is the period for Shaoyang disease onset. Without exterior symptoms such as aversion to cold, fever, headache, and fullness and distress in the chest and hypochondrium, nor interior symptoms like abdominal pain, vomiting, cough, or thirst, but merely presenting with palpitations and irritability, it indicates that the Shaoyang pivot has been affected by cold, causing Wood pathogen to carry Ministerial Fire (Xiang Huo) to cause pathology. When Ministerial Fire is excessive, Sovereign Fire (Jun Huo) becomes deficient. The true fire within the Heart (Li Trigram) fails to be concealed, resulting in palpitations; the insufficiency of true fire within the Heart leads to irritability. If one does not use acrid-sweet herbs to assist Yang and sour-bitter herbs to maintain Yin, the Middle Qi will perish. Therefore, Xiao Jian Zhong Tang is formulated to regulate Shaoyang, supplementing the deficiencies of Xiao Chai Hu Tang (Minor Bupleurum Decoction). Although palpitations and irritability originally belong to Chai Hu (Bupleurum) patterns, Chai Hu Tang is not used here because the text first mentions Shanghan without fever, implying that aversion to cold exists without fever. Palpitations accompanied by irritability indicate that cold damages Shen (Spirit) and heat damages Qi. Within two or three days, heat has entered the interior while cold remains on the exterior, constituting a half-exterior, half-interior pattern. However, since there are no alternating chills and fever, Xiao Chai Hu Tang is not appropriate. For palpitations, Huang Qin (Scutellaria Root) should be removed; for irritability without vomiting, Ren Shen (Ginseng Root) and Ban Xia (Pinellia Tuber) should be removed. Thus, Gui Zhi (Cinnamon Twig) serves as the sovereign herb to unblock the Heart and dissipate cold; Gan Cao (Licorice Root), Da Zao (Jujube Fruit), and Yi Tang (Malt Sugar) act as assistant herbs to strengthen the Spleen and calm palpitations; Shao Yao (Peony Root) is doubled to drain fire and relieve irritability; Sheng Jiang (Fresh Ginger) is employed to utilize Metal properties to pacify Wood. Although this formula is essentially Gui Zhi Tang (Cinnamon Twig Decoction) with added Yi Tang and doubled Shao Yao, it does not exceed the method of modifying Xiao Chai Hu Tang. Named "Jian Zhong" (Construct the Middle), it implies achieving exterior resolution through non-diaphoretic means. It is called "Xiao" (Minor) because only half its action resolves the exterior, rather than completely consolidating the Middle Jiao. After erroneous sweating in Shaoyang disease, if Stomach disharmony causes irritability leading to restlessness, Xiao Chai Hu Tang is suitable for clearing; if sweating has not yet occurred and Heart Qi is already deficient, causing irritability due to palpitations, Xiao Jian Zhong Tang is suitable for harmonizing.

In Taiyang cold damage, if the pulse at the Cun (inch) position is choppy (Se) and the pulse at the Chi (cubit) position is wiry (Xian), according to medical principles, acute abdominal pain should occur. Initially treat with Xiao Jian Zhong Tang; if ineffective, then treat with Xiao Chai Hu Tang.

If both Chi and Cun pulses are wiry, it indicates Shaoyang disease. Now, with a choppy Yang (Cun) pulse and a wiry Yin (Chi) pulse, it indicates that cold has damaged the Jueyin channel, not Shaoyang. The Cun position belongs to Yang, governing the exterior; a choppy Yang pulse indicates that Yang Qi is not free-flowing and exterior cold is unresolved. A wiry pulse represents a Wood pathogen, which must carry Ministerial Fire. Since Ministerial Fire cannot resist cold, it must retreat into the Jueyin channel to cause pathology. The Jueyin channel reaches the lower abdomen, wraps around the Stomach, connects to the Liver, and links to the Gallbladder; thus, the abdomen is all within the domain of Jueyin. The Chi position belongs to Yin, governing the interior. A wiry Yin pulse, being the Liver pulse, necessarily indicates acute abdominal pain. The Liver dislikes constraint; sweet flavors relax tension, sour flavors drain excess, and acrid flavors disperse pathogens. This is why Xiao Jian Zhong Tang is the initial move for Jueyin to drive out cold, resolve the exterior, pacify the Liver, and expel pathogens. However, when pathogens are in Jueyin, abdominal pain is inevitable, which is originally a critical condition. One dose of Jian Zhong may not succeed. If the condition does not improve, one should subsequently use Chai Hu to guide the pathogen to Shaoyang, providing an exit route. This is what is meant by "when Yin emerges to Yang, healing occurs," and also illustrates using Xiao Chai Hu Tang to supplement the limitations of Xiao Jian Zhong Tang.

The previous clause differentiates syndromes, while this clause differentiates pulses. The previous clause describes Shaoyang Ministerial Fire invading the Heart causing irritability, where the syndrome is obvious; this clause describes Jueyin Ministerial Fire attacking the abdomen causing pain, where the syndrome is subtle. If abdominal pain is not caused by Ministerial Fire, the cold nature of Shao Yao should not be used. The *Nei Jing* states: "Sudden diarrhea and abdominal distension all belong to heat." This explains the rationale for using Shao Yao for abdominal pain in this context.

One might ask: Before treating abdominal pain with the warming Xiao Jian Zhong Tang, and later with the cooling Xiao Chai Hu Tang, was Zhang Zhongjing merely experimenting? The answer is no. "Not improved" means not yet healed, not that the condition has worsened. First, Xiao Jian Zhong Tang resolves the muscle layer and releases the exterior, with pain relief attributed to Shao Yao; subsequently, Chai Hu Tang tonifies the middle and expels pathogens, with pain relief attributed to Ren Shen. According to the modification rules of Chai Hu Tang, for abdominal pain, Huang Qin is removed and Shao Yao is added, which is more potent than Jian Zhong. Is there really a difference between warming and cooling? Because the Yang pulse remains choppy, Ren Shen is used to assist Gui Zhi; because the Yin pulse remains wiry, Chai Hu is used to assist Shao Yao. If the patient recovers after one dose, why would one need the warming tonification of Ren Shen or the ascending-descending action of Chai Hu? Zhang Zhongjing uses two formulas for one syndrome in cases such as using Ma Huang Tang (Ephedra Decoction) for diaphoresis, and if vexation recurs after half a day, using Gui Zhi Tang for further diaphoresis, following the same principle. However, these are strategies to control disease, not absolute certainties. Using Ma Huang followed by Gui Zhi is a method from exterior to interior; using Xiao Jian Zhong followed by Xiao Chai Hu is a method from interior to exterior.

Patients prone to vomiting should not use Xiao Jian Zhong Tang because of its sweet flavor.

This is a contraindication for Xiao Jian Zhong Tang, similar to the principle that patients with alcohol accumulation should not take Gui Zhi Tang. Irritability with frequent vomiting, and vomiting with fever, are Chai Hu patterns. Heat in the chest with abdominal pain and desire to vomit is a Huang Lian Tang (Coptis Decoction) pattern. Combined disease of Taiyin and Shaoyang with spontaneous diarrhea and vomiting is a Huang Qin Tang (Scutellaria Decoction) pattern.

**Xiao Jian Zhong Tang Formula:**
Gui Zhi (Cinnamon Twig, remove bark) 3 liang, Sheng Jiang (Fresh Ginger) 3 liang, Shao Yao (Peony Root) 6 liang, Zhi Gan Cao (Honey-fried Licorice Root) 2 liang, Da Zao (Jujube Fruit, broken) 12 pieces, Jiao Yi (Malt Sugar) 1 sheng.
Boil in 7 sheng of water to obtain 3 sheng, remove dregs, add Jiao Yi, and gently heat until dissolved. Take 1 sheng warm, three times daily.