Fructus Aurantii (Zhi Qiao, 枳壳) is the dried immature fruit of Citrus aurantium (Bitter Orange) — closely related to but distinct from Zhi Shi (枳实, the younger, smaller fruit), which is more powerfully breaking and descending. Zhi Qiao is the larger, more mature fruit, with a milder, broader action on Qi regulation — particularly suited to conditions of the chest and flanks where a gentler approach is needed.

Bitter, pungent, and slightly cold in nature, Fructus Aurantii enters the Spleen and Stomach channels. Its primary action is to promote Qi movement, reduce distension, and relieve the fullness, bloating, and oppressive sensation of Qi stagnation in the chest, flanks, and abdomen. It also transforms phlegm-damp when dampness and Qi stagnation combine to obstruct the middle and upper burners. Its milder nature compared to Zhi Shi makes it preferred for conditions requiring long-term Qi regulation without excessive descending force.

Fructus Aurantii has been used in Chinese medicine since the Han Dynasty, with a clear distinction between the immature fruit (Zhi Shi) and the more mature fruit (Zhi Qiao) established in classical texts and maintained in clinical practice to this day.