Bu Zhong Yi Qi Tang   补中益气汤   Tonify the middle and augment the qi decoction

Discussion:
This is an important and characteristic formula from the Pi Wei Lun, or Discussion on the Spleen and Stomach, by Li Dong Yuan. A major school of practice is based on this treatise and this formula in particular.

“If there is irregularity of food and drink or inappropriate [intake] of hot and cold, then the spleen-stomach are damaged. Joy, anger, anxiety, and fear can all injure the source qi. When the spleen-stomach qi is debilitated and the source qi is insufficient, the heart fire is solely exuberant. Heart fire is yin fire. It starts in the lower burner and then converges in the heart. The heart loses governance and then the ministerial fire replaces it. The ministerial fire is the fire of the pericardium in the lower burner and it is the enemy of the source qi. Fire and source qi lose their positions; one is overcome and one is vanquished. In spleen-stomach qi vacuity, the qi descends into the kidney. Yin fire then exploits the earth’s position.”  (Pi Wei Lun by Li Dong Yuan)

The formula is organised around the treatment principle from the Nei Jing that fatigue and weakness are treated by warming and that deficiency is treated by augmenting. It uses sweet warm medicinals to supplement the center and upbear center yang. When poor eating habits and excessive work damage the spleen and stomach, center yang falls down and yin fire floats upwards, resulting in heat and heart vexation, different from external heat repletion pattern.

In patterns of spleen-stomach vacuity, heart fire is hyperactive because of dietary taxation. It exploits earth. Secondarily, the lung receives the evil. It is thus necessary to use Huang Qi in the highest [dosage], then Ren Shen and Zhi Gan Cao. As the spleen-stomach become vacuous, the lung qi expires first. Therefore, use Huang Qi in order to boost [the qi] of the skin and body hair so as to block the interstices and not allow spontaneous sweating to damage the source qi. And for upper wheezing and shortness of breath, use Ren Shen to supplement. When heart fire exploits the spleen, the sweetness of Zhi Gan Cao is needed to drain heart fire and supplement the source qi within the spleen-stomach. If the spleen-stomach is acutely painful then it is greatly vacuous. There is contractile tension in the abdomen and it is appropriate to use larger amounts [of Zhi Gan Cao]. As the Nei Jing says, “for tension, moderate it.’’ Bai Zhu is bitter, sweet and warm. It eliminates heat in the stomach and disinhibits blood between the back and the umbilicus. The clear qi of the stomach is below; thus, it is necessary to use Sheng Ma and Chai Hu to conduct it [upward]. [This also] conducts the sweet warm qi and flavor of Huang Qi and Gan Cao upward, thereby supplementing the dissipating stomach qi and making the exterior replete. This also moderates the contractile tension in the girdling vessel (dai mai). These two medicinals [Chai Hu and Sheng Ma] are bitter and neutral. Thin flavors are yang within yin and conduct the clear qi upward. When the qi becomes chaotic in the chest, this is interference between the clear and the turbid. Use Chen Pi from which the white has been removed to rectify the qi. It also assists the upbearing of the yang qi by dissipating stagnant qi. Its use is to assist the sweet and acrid [ingredients]. For dry mouth and throat, add Ge Gen. Vacuous spleen-stomach qi is unable to upbear; this is yin fire damaging the engendering and effusion of qi. The construction-blood is debilitated. The construction qi is not nourished. Yin fire blazes exuberantly. There is fire hidden within the blood that brews day by day. Qi and blood decrease daily. The heart and pericardium govern the blood. As blood decreases, the heart is not nourished. The heart becomes chaotic and there is vexation; this disease is called man2. Man2 is heart bewilderment with vexation, oppression, and disquiet. Thus, add acrid, sweet, slightly warm formulas to engender yang qi. As yang is engendered, yin grows. Another question, how is it that sweet warm [medicinals] are able to engender blood? The answer lies in the methods of Zhang Zhong-Jing. For blood vacuity, supplement with Ren Shen. Effulgent yang is able to engender yin-blood. Additionally, use Dang Gui to harmonise. Add a small [amount] of Huang Bai to rescue kidney water and to drain the hidden fire with in the yin. If the vexation does not cease, add a small amount of Sheng Di Huang to supplement kidney water. When water is effulgent, heart fire spontaneously downbears. If floating qi makes the heart chaotic, settling it with Zhu Sha An Shen Wan will lead to recovery.  Nei Wai Shang Bian Huo Lun – Li Dong Yuan

Etiology:
The head is the confluence of all yang. Clear yang should rise to the head. When it does not turbid qi counter flows to the head and causes headache with comes and goes. (Externally contracted headaches often are more constant in nature.) There is spontaneous sweating because deficiency of qi and yang fails to defend the exterior. Dislike of speaking and activity are due to qi deficiency.

Spleen deficiency leads to poor appetite and fatigued limbs. Spleen and stomach vacuity leads to lung qi deficiency with shortness of breath. There is thirst from insufficient lung qi failing to spread fluids. From the spleen deficiency there is failure to upbear clear center yang, so it falls downward, leading to diarrhea and dysentery. When the right qi is vacuous and falls inward and contends with evil qi there is alternating heat and cold. Because the yang does not always fail to ascend many of the symptoms come and go.

Discussion of Ingredients:
Huang qi strongly augments the qi. As lung is the root of qi, it is the chief medicinal to support the lung.
Ren shen supports the original qi, fortifies the spleen, boosts qi.
Gan cao harmonises the center and boosts the spleen. In combination with the above 2 it clears heat. Li Dong Yuan considered this combination as excellent for eliminating vacuity heat vexation.
Bai zhu dries damp and strengthens the spleen
Dang gui harmonises the blood and yin
Chen pi harmonises the flow of qi, balances the contending of clean and turbid qi, and prevent sweet flavored medicinals from causing fullness and stagnation.
Sheng ma and chai hu upbear the clear yang of the yang ming and shao yang and also lift the downward falling clear qi of the middle jiao. When clear yang ascends, turbid qi descends.
Shang jiang and da zao harmonise ying and wei, help distribute the fluids and pen the interstices (cou li).

“The spleen and stomach like sweetness and have aversion to bitterness; like supplementation and hav aversion to to attacking; like warmth and have an aversion to cold; like openness and have an aversion to stagnation; like upbearing and have an aversion to downbearing; like dryness and have an aversion to dampness. This formula fulfils all these requirements.” Yi Guan or Thorough Knowledge of Medicine by Zhao Xian Ke