Dear Dr. Jiang:
I feel frustrated in my attempts to use xiao chai hu tang in my practice. The books all say this is a very important clinical formula, but it seems no one ever comes into my practice with the primary symptoms of the shao yang pattern, i.e., distinctly alternating chills and fever.
A Little More Chai Hu
Dear ALMCH,
First of all, the shao yang pattern is not the same as malaria, referred to as nue ji in Chinese medicine. Nue ji is characterized by fever and chills that alternate at regular defined intervals, such as every other day (jian ri nue) or every third day (san ri nue). The alternation of fever and chills in the shao yang pattern does not necessarily occur at regular intervals, and can repeat many times in a single day.
The classical shao yang pattern can develop as a result of four distinctive etiologies:
- External evils can attack tai yang first, then penetrate into the shao yang level; this is the most common etiology.
- External evils can directly attack shao yang.
- As patients improve in the jue yin level, stagnating yang qi can externalize as it is being released and move back out into the shao yang level.
- Patients with pre-existing liver-gall bladder disharmonies, such as depression of liver qi, can develop a kind of shao yang pattern when they are attacked by external evil, since the external pattern serves to make the underlying stagnation worse.
All of the above are classical shao yang etiologies; all are treated with xiao chai hu tang; and all involve external pattern symptoms with alternating chills and fever, but the Jin Gui Yao Lue states that xiao chai hu tang can also be used to treat jaundice, vomit and abdominal pain, even in the absence of chills and fever. Even in ancient times, xiao chai hu tang was not necessarily restricted to the treatment of the typical shao yang pattern. These days, the application of this formula has been extended much farther.
It is often used, for example, to treat disharmony between the liver/gall bladder and the stomach/spleen, especially if qi stagnation has transformed into fire. The patient needs not have chills or fever for this formula to be applicable. Because xiao chai hu tang is effective at rebuilding stomach qi, it is better for nausea than chai hu shu gan tang or xiao yao san. Furthermore, it is better than si ni san, if the liver-spleen disharmony occurs with more symptoms of deficiency. This is one of the reasons why xiao chai hu tang is often used to treat chronic hepatitis and digestive disorders. It also explains its use in the treatment of depression and taciturnity (mo mo) with lack of desire to eat.
Xiao chai hu tang also can be used as a preventive formula in the treatment of "recurring" external invasions, i.e., external patterns that keep coming back. This is a common presentation in respiratory allergies. External patterns can recur as a result of unresolved evil from previous invasions, or from repeated new attacks in patients with weak constitutions. Xiao chai hu tang can be used in either scenario, since the formula contains both tonifying and dispelling ingredients. It exemplifies the principle, "Support the right and dispel evil" (fu zheng qu xie). Even if the exterior symptoms are completely gone, xiao chai hu tang contains enough tonifying ingredients (ren shen, zhi gan cao and da zao) to be continued safely as a long-term preventive therapy.
Of course, there are other formulas that can support the right qi and prevent recurring external invasions. Yu ping feng san and huang qi jian zhong tang are both used for this purpose, but these formulas are warming and therefore less useful when the recurring pathogen is wind heat, or if transformed internal heat has caused constipation. In such circumstances, the slightly cooling properties of xiao chai hu tang, together with its ability to release liver stagnation and downbear stomach qi, offer the practitioner unique strategic advantages.
It is often forgotten that the formula's chief herb, chai hu, is useful not only in harmonizing shao yang, but in dispelling wind heat. Thus, xiao chai hu tang can be used for general wind heat patterns causing headaches, especially if the pain is on the lateral side (i.e., the shao yang region). For the same reason, vertigo, visual disorders and hearing disorders all fall under the domain of xiao chai hu tang when they occur with exterior patterns. Even in the absence of exterior patterns, xiao chai hu tang can still be useful if the above symptoms are caused by liver stagnation transforming into fire in an individual who is too weak or qi deficient for the much stronger long dan xie gan tang.
According to ancient etiological theories, a deficient body is easily attacked by external evil. This evil tends to gravitate to the hypochondrium, where it stagnates, transforms into fire and ascends, causing nausea; bitter taste; blurred vision; dizziness, etc. This is why we need cooling formulas to treat the shao yang pattern, and xiao chai hu tang is slightly cooling - but not so cooling that it is completely contraindicated in conditions of yang qi deficiency. In such cases, the formula can be modified by adding rou gui or gan jiang, or by removing huang qin. These modifications are particularly important if the patient has diarrhea.
In summary, the best way to understand xiao chai hu tang is through an analysis of its ingredients and their mutual synergy, not through rigid application of the classical shao yang pattern symptomology. Because it tonifies qi, while at the same time reducing stagnation, this formula can be used to treat the myriad symptoms of liver-spleen disharmony. Because it is slightly cooling, it is especially effective if there is some heat present, and even qi-deficient patients tend to develop some degree of heat when there is stagnation. This is a great formula, and I hope you can now use a "little more" xiao chai hu tang in your practice.
Edited with the assistance of John Pirog, MSOM.
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