People often say that Yi Tang (Maltose) is the King herb in Xiao Jian Zhong Tang. Additionally, they suggest that Xiao Jian Zhong Tang changed from 'a formula for common-cold' to 'a formula for gastrointestinal symptoms' because Yi Tang was added to Gui Zhi Tang. However, this isn't true.
1. It is a digestive formula even without Yi Tang firsthand
Firstly, there is a prescription called Gui Zhi Jia Shao Yao Tang. This formula shares the same composition as Gui Zhi Tang with the addition of Shao Yao. This formula, like Xiao Jian Zhong Tang, serves as a digestive prescription. The difference between the two is that Gui Zhi Jia Shao Yao Tang is typically used for adults, while Xiao Jian Zhong Tang is primarily used for children.
本太陽病, 醫反下之, 因爾腹滿時痛者, 屬太陰也, 桂枝加芍藥湯主之
There is a case when the Tai Yang disease is medically discharged, and the person with abdominal fullness and pain belongs to Tai Yin. The principal prescription for this is Gui Zhi Jia Shao Yao Tang."
虛勞裏急悸衄腹中痛, 夢失精四肢痠疼, 手足煩熱, 咽乾口燥, 小建中湯主之
In the case of lethargic, agitation, palpitations, nosebleeds, abdominal pain, dream emission, fatigue, irritability, dry throat, dry mouth, Xiao Jian Zhong Tang is the right treatment.
Certainly, the addition of Yi Tang strengthens the Spleen tonic effect, but its usage for spasmodic abdominal pain remains unchanged. The inclusion of Yi Tang does not change a cold prescription into a digestive one. Some might argue that the addition of Shao Yao changes a cold prescription into a digestive one. However, Gui Zhi Jia Shao Yao Tang, a formula with the same composition but without Yi Tang, is also a digestive formula. In actual clinical use, Gui Zhi Tang is used for conditions other than colds, such as sciatica, trauma, and digestive pain. This is mentioned in your textbooks.
Ah, it's sad. Why do people think that to treat a different condition, the ingredients must differ, as in Western medicine? Herbal medicine is simple. The warming and soothing energies of Gui Zhi and Shao Yao can treat colds, trauma, Yang deficiency, digestive pain, and any condition involving tightness and coldness.
2. How could the optional herb be the King herb?
Next is the method of adjusting from your textbook.
"With a sallow complexion. fatigue and tiredness. remove Yi Tang (Maltosum) and add Ren Shen (Radix et Rhizoma Ginseng), Huang Qi (Radix Astragali) and Dang Gui (Radix Angelicae Sinensis)." - Chinese Herbal Formulas and Applications by John Chen, page 427
When treating Qi deficiency by adding Huang Qi and Ginseng, the advice is to remove Yi Tang. Wait, the King herb is removed? In actual clinical practice, when using Xiao Jian Zhong Tang for adults, Yi Tang is commonly removed. Notably, when using Gui Qi Jian Zhong Tang or Dang Gui Jian Zhong Tang, Yi Tang is removed. Do you think that the King herb can be removed when modifying the formula? It is just a lack of understanding of TCM formulas to think that Gui Zhi Tang becomes a different medicine simply by adding Yi Tang.
Ah, it's sad. Why do people think that to treat a different condition, the ingredients must differ, as in Western medicine? Herbal medicine is simple. The warming and soothing energies of Gui Zhi and Shao Yao can treat colds, trauma, Yang deficiency, digestive pain, and any condition involving tightness and coldness.