This is an excerpt from one of Dr. Hu’s books. It is an elucidation of clause 100 of the Shang Han Lun (On Cold Damage)

In cold damage (1), when the Yang pulse is choppy(2) and the Yin pulse is wiry(3), there should be acute abdominal pain (4) . First administer Xiao Jian Zhong Tang (5) . If there is no reduction (of symptoms), Xiao Chai Hu Tang governs (6).

Interpretation:
A pulse that is floating and choppy, is what is meant by the ‘Yang pulse is floating; at the deep level the pulse is wiry, which is written as ‘the Yin pulse is wiry’. A choppy pulse governs scanty blood and wiry governs cold exuberance. What we have here is cold damage with a floating choppy pulse and a deep wiry pulse, which signifies external blood vacuity and cold exuberance in the interior. According to these laws we should expect to see acute abdominal pain therefore Xiao Jian Zhong Tang is given.
After taking the decoction there is still no reduction of symptoms which means that the condition has yet to be resolved and because Shao Yang has the same pulse (wiry) this is considered a Tai-Yang Shao-Yang combination disease with interior cold. Xiao Jian Zhong Tang only partially treats this condition, therefore we administer Xiao Chai Hu Tang in order to resolve Shao Yang evils, and only then can we offer a cure.

Notes:
Acute abdominal pain originally belongs to both a Xiao Jian Zhong Tang pattern and to a Xiao Chai Hu Tang pattern. Ordinarily Shao yang harbors internal vacuity and central qi insufficiency and although there are Xiao Chai Hu Tang signs, we must first fortify the centre. First Xiao Jian (Zhong Tang), afterwards Chai Hu (Tang). In vacuity treating the interior first is a fixed concept, and rather than treating with the first rule of Xiao Jian Zhong Tang with no effect, it is treated with Xiao Chai Hu Tang. If in abdominal pain the pulse is wiry, this is only interior vacuity and Xiao Jian Zhong Tang can be administered without any relation to Shao Yang.

Xiao Jian Zhong Tang  小建中汤

Gui Zhi (remove skin) 3 liang
Shao Yao 6 liang
Sheng Jiang (cut) 3 liang
Da Zao (broken) 12 pieces
Gan Cao (honey fried) 2 liang
Jiao Yi 1 sheng

For the above six ingredients, use seven sheng of water. Boil until three remain, and remove the dregs. Add the malt sugar and put back on low heat until it melts. Take one sheng warm three times daily. People who vomit easily should not take this decoction due to its sweetness.

Formula interpretation:
The first five ingredients of this formula make up Gui Zhi Jia Shao Yao Tang (Tai-Yin, clause 284), which treats Tai-Yang disease abdominal fullness and periodic pain found after purgation. Adding Yi Tang which is warm and sweet makes it more supplementing. Shao Yao is bitter, sour and slightly cold and by adding the warmth of Yi Tang we have mild supplementation. This is Xiao Jian Zhong Tang.

Jiao Yi is sweet, warm, enriching, nourishing and strengthening. It relaxes tension, strengthens the Spleen and Stomach, boosts Qi and supplements vacuity cold. It governs acute abdominal pain and rumbling intestines (borborygmus). The nature and flavor of both Jiao Yi and Gan Cao are quite similar and are used for Yin, Yang, Exterior, Interior, Repletion and Vacuity, but are especially indicated in interior vacuity. They are unsuitable in abdominal pain due to excessive gastric acid.
Shao Yao is bitter, slightly cold and has the function of mild precipitation.
Jiao Yi and Bai Shao effectively treat abdominal pain, but differentiation must be made between cold, heat, vacuity and repletion. The abdominal pain associated with intestinal tuberculosis offers an opportunity to use this combination.

Notes:
Abdominal pain is found in both vacuity and repletion. Pain on palpation that is not severe even with stronger pressure belongs to Qi pain. Pain on pressure with hardness that refuses pressure is seen in accumulations and gatherings. Qi type pain should not be purged.

1. ‘Cold damage’ signifies Tai-Yang cold damage where the exterior has yet to be resolved. We do know that Xiao Jian Zhong Tang treats the abdominal pain and Xiao Chai hu Tang treats the disease if there is no reduction or lessening of symptoms. This clause is originally a Tai-Yang and Shao-Yang combination disease with interior vacuity cold.
2. ‘Yang pulse is choppy’ means the pulse is felt at a superficial level, plus liquids and blood are not filling and nourishing the exterior and the stomach is weak.
3. ‘Yin pulse is wiry’ means the pulse has a wiry quality at the deep level. A wiry pulse is thin and with strength
4. Acute pain and hyper-tonicity with pain. By the yang pulse being choppy and the yin pulse wiry, we are able to see that there is an insufficiency of liquids and blood and cold exuberance in the interior, so there should be hypertonic pain in the abdomen.
5. Xiao Jian Zhong Tang is a modified version of Gui Zhi Tang. Both these formulas can resolve the exterior, enrich and nourish the blood vessels and through its warm and sweet nature expel cold and stop pain. We can deliberate the meaning of ‘first administer’. In Tai-Yang Shao-Yang combination disease with the addition of vacuity cold in the interior, we should first save the interior and then resolve the exterior or half exterior, half interior aspect. This is the essence and spirit of clauses 93 and 94.
6. No reduction of symptoms, namely means that after taking Xiao Jian Zhong Tang the abdominal pain is not completely gone. Now because both Xiao Jian Zhong Tang and Xiao Chai Hu Tang symptoms exist, we first treat the interior and afterwards the exterior. Since Xiao Jian zhong Tang only treated half the condition we follow it with Xiao Chai Hu Tang to effect a complete resolution of symptoms