Wood of Water: Huang Qin 黃芩

味苦皆屬水，地黃為之主，黃芩為木，黃連為火，白術為土，竹葉為金。

All bitter belongs to water; it is governed by Dihuang, Huangqin is wood, Huanglian is fire, Baizhu is earth, and Zhuye is metal.

Huangqin 黄芩, also known as Scutellaria baicalensis or skullcap root, is classified by the Tang Ye Jing as the Wood of Water. The Shen Nong Ben Cao Jing's entry for Huang Qin states:

味苦平。主治諸熱黃疸，腸澼洩利，逐水，下血閉，惡瘡疽蝕，火瘍。一名腐腸。生川谷。

Huangqin tastes bitter and neutral. It governs all hot yellowing disorders, intestinal afflux, diarrhea and dysentery, expelling water, descending blood obstruction, [treating] malign sores, subcutaneous ulcers, erosions [of the flesh], and firey sores. Another name for it is Fu Chang (腐腸 Putrid Intestines). It grows in rivers and valleys.

Based on this passage, we can deduce that Huangqin is an herb that powerfully clears heat by virtue of its bitter flavor. It’s a very commonly encountered herb in the Shang Han Lun and Jin Gui Yao Lue, where it is often paired with Chai Hu to harmonize disease in the Shaoyang, as in Xiao Chaihu Tang (小柴胡湯) and its variations. And from seeing its application as a Shaoyang herb, we will be able to understand why it is classified as the Wood of Water.

It may be helpful to briefly review Six Conformations (六經 Liu Jing) theory here.

Shaoyang’s function is described as pivoting (樞 shu), it governs the Ministerial Fire (相火 xiang huo), and it encompasses both the San Jiao, which from a Five Phase perspective belongs to Fire, and the Gallbladder, which belongs to Wood. From this lens, Shaoyang pathology can be understood as arising from the dysfunction of Ministerial Fire – the cardinal signs of a Shaoyang pattern are described as “a bitter taste in the mouth, dry throat, dizzy vision” (口苦，咽乾，目眩) in the Shang Han Lun. 

From a Six Conformations perspective, this symptom complex can all be attributed to the flaring of Ministerial Fire. However, from a Five Phases perspective, we might describe this same pathology in in terms of Wood and Fire – dysfunction of the generating cycle, wherein Wood feeds too quickly into the Fire phase, causing flaring of Fire and the various heat signs seen in Shaoyang syndrome. In either case, the remedy for an excess of Fire is Water.

Huang Qin, image courtesy of Kamwo Herbs

This is in keeping with the direction of Water, which the Neijing associates with the season of Winter and the concept of going into storage (cang 藏). The direction of Fire, in contrast, is to move upward and outward; it is associated with the activity of Summer, which is growth (zhang 長) and expansion.

These are in effect opposing actions, and the dynamic balance between Fire and Water is the basis for normal physiology in the microcosm of the body and the orderly movements of the seasons in the macrocosm of the cosmos.

We know from Five Phase theory that the Child of any given phase can drain its Parent, and we can apply this metaphor to the concept of Wood and Ministerial Fire – if Fire rages out of control, it will eventually consume Wood. Bringing a healthy dose of Water in the right way does not douse the Fire, but causes it to descend, become consolidated, and stored in a way that it can do its appropriate work of warming and moving without destroying the base upon which it feeds.

Huangqin’s bitter flavor brings the cooling activity of Water to Wood by descending and clearing congested Ministerial Fire in the Gallbladder. It synergizes with Chaihu to accomplish this purpose. Chaihu moves and releases Gallbladder qi, while Huangqin drains fire; together they harmonize the Shaoyang.

Chaihu and Huangqin are paired together so commonly in the Shang Han Lun and Jin Gui that is sometimes difficult to seperate their actions, however the action of Huangqin alone is illustrated in a lesser known formula called Huangqin Tang (黃芩湯).

Huangqin Tang is discussed in Line 172 of the Shang Han Lun:

太陽與少陽合病，自下利者，與黃芩湯

When in taiyang and shaoyang combination disease there is spontaneous diarrhea, it is suitable to give Huangqin Tang.

The symptom of “spontaneous diarrhea” is consistent with the indications of Huangqin listed in the Shen Nong Ben Cao Jing (as well as the colorful alternative name of Fuchang, “Putrid Intestines!”). 

There is some debate among different commentators about how to understand the pathophysiology behind diarrhea in a Taiyang and Shaoyang combination disease, but one interpretation is that heat in the Gallbladder is transferred to the Small Intestine, causing damp heat type diarrhea or dysentery. Like other Shaoyang patterns, this a problem of obstructed and stagnant Ministerial Fire, however this in particular pattern, Ministerial Fire stagnates in the fu organs instead of in the channels and collaterals or the sensory orifices.

As with all Shaoyang patterns, the Huangqin Tang pattern involves Wood and Fire, and is addressed by using Huangqin to bring the activity of Water into the realm of Wood, by draining Gallbladder heat. It is also interesting to consider the etiology of the kind of diarrhea described in this passage, as well as the composition of the formula. Huangqin Tang consists of the ingredients Huangqin (the Wood of Water) and also Shaoyao (the Earth of Metal) as well as Dazao (the Fire of Earth) and Gancao (the Wood of Earth).  Shaoyao, as the Metal of Earth, can help to control Wood, while the combination of Shaoyao and Gancao together relaxes and soothe urgency. Dazao, as the Fire of Earth, brings the activity of Earth into the realm of Fire; its sweet flavor is able to drain excessive fire through the generating cycle. This ability is accentuated by pairing with Gancao.

If you've read this far, hopefully you'll agree with me that Huangqin is a particularly good herb to illustrate how both the Five Phases and the Six Conformations can be understood together. And you can probably see how Huangqin Tang is a good example of how combining the perspectives of both Five and Six can give us insights into how to treat diseases.