XiaoRadix Bupleuri (Chai Hu) 9g, Radix Scutellariae Baicalensis (Huang Qin) 9-12g, Radix Panacis Ginseng (Ren Shen) ~9gmix-fried, Radix Glycyrrhizae (Gan Cao) 3-6g, Fructus Zizyphi Jujubae (Da Zao) 3-5 piecesuncooked, Rhizoma Zingiberis (Sheng Jiang) 2-3 slices.
Xiao Chai Hu Tang is mild and can be used for many different types of problems besides disharmony between the interior and exterior. It can be used for internal disharmonies such as zang-fu patterns involving the liver and spleen, spleen and stomach, and the stomach and intestines. In addition, it can be used for reversal patterns including these Yin Fire concepts of Li Dong Yuan. These include ministerial fire (flushing due to emotions) that tends to rise through the shao yang, spleen qi vacuity with damp sinking down causing dampness and heat wherein the heat rises, qi stagnation that results in heat that rises.
The classical shao yang pattern can develop as a result of four
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
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
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.