Which herbs are used for focal distention, fullness, dryness and hardness in Cheng Qi Tangs?

• A. Da Huang, Mang Xiao, Zhi Shi, Hou Po
• B. Da Huang, Gan Cao, Chen Pi, Ju Hua
• C. Da Huang, Mang Xiao, Zhi Shi, Hou Po
• D. Zhi Shi, Hou Po, Qing Hao, Da Huang

Answer: (C)

Focal distention with fullness and hardness in this pattern comes from heat with internal stagnation in the intestines, so the approach is to purge the accumulation while moving qi and drying dampness. The four herbs work together to accomplish this.

Da Huang provides the downward purge and clears heat from the intestines, directly addressing the accumulation that causes fullness and hardness. Mang Xiao softens dryness and helps the stool soften, making the purgation gentler and more complete. Zhi Shi breaks up clumping and directs the action downward, reducing distention and helping the purge to move through the bowels. Hou Po moves qi, alleviates abdominal fullness, and dries dampness, which further relieves distention and prevents stagnation from impeding the purge.

Together these actions target the root pattern—heat with stagnation causing distention and hardness—by combining a strong purgative with agents that soften, regulate qi, and dry dampness. Other formulas or herb sets either omit one of these four roles or include herbs not characteristic of this pattern, which is why this combination best fits Cheng Qi Tang for these symptoms.