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[Flavor and Nature] Bitter, cold, non-toxic. It is indicated for major wind pathogens residing in the skin, manifesting as itching and discomfort resembling millet grains or beans; it resolves cold-heat complex, stops dysentery, promotes muscle growth, benefits the five zang organs, and tonifies qi.

Zhang Yin'an stated: Zhiqiao (Aurantii Fructus) has a bitter and cold flavor. It does not shed leaves in winter, inheriting the qi transformation of Shaoyin's root and branch. Its fragrance is aromatic, its shape is round, its flowers are white with thorns, and its pulp is yellowish-white, thereby acquiring the metal and earth qi transformations of Yangming. Its indication for major wind in the skin, causing itching like millet grains or beans, is due to mastering wind via Yangming metal qi and clearing heat via Shaoyin water qi. Resolving cold-heat complex is achieved by inheriting Shaoyin's root hot qi to dispel cold and its branch yin qi to clear heat. Stopping dysentery and promoting muscle growth stems from obtaining Yangming central earth qi. The five zang organs originate from congenital Shaoyin and grow via postnatal Yangming; thus, it benefits the five zang organs. Acquiring Shaoyin's yin allows it to tonify qi, while obtaining Yangming's qi lightens the body. In Zhongjing's original treatise, Dachengqi Tang (Major Order the Qi Decoction) uses roasted Houpo (Magnolia Bark) and roasted Zhishi (Immature Bitter Orange); Xiao Chengqi Tang (Minor Order the Qi Decoction) uses raw Houpo and raw Zhishi. The distinction between raw and roasted holds significant meaning, which students must carefully contemplate.

According to the *Shennong Bencao Jing* (Divine Farmer's Materia Medica), Zhishi (Immature Bitter Orange) is recorded, but Zhiqiao (Aurantii Fructus) is not; they were distinguished starting from the Tang Dynasty's *Kaibao Bencao*. However, Zhiqiao is simply the larger form of Zhishi. Its nature is dispersing and its qi scatters, unlike Zhishi which is more consolidated. Since they are of the same species, excessive distinction is unnecessary.

[Flavor and Nature] Bitter, cold, non-toxic. It treats internal heat accumulation in the five zang organs and intestines/stomach, jaundice, intestinal hemorrhoids, stops diarrhea and dysentery, and treats leukorrhea (red and white discharge) and erosive sores in the female genitalia.

Chen Xiuyuan stated: Huangbai (Phellodendri Cortex) has a cold nature, inheriting the cold water qi of winter. Its bitter and non-toxic flavor corresponds to the fire element of the southern direction; its thick bark and yellow color correspond to the transformation of Taiyin central earth. The five zang organs belong to yin; therefore, any herb described as "governing the five zang" primarily acts on yin aspects. Treating heat accumulation in the intestines and stomach relies on coldness to clear heat. Treating jaundice and intestinal hemorrhoids relies on bitterness to overcome dampness. Stopping diarrhea and dysentery works because only bitter-cold herbs can eliminate damp-heat dysentery and simultaneously strengthen the body.

Fetal leakage and bleeding in women result from reckless movement of blood due to heat; red and white leukorrhea, as well as erosive sores in the vaginal opening, are caused by damp-heat sinking downward. Huangbai clears heat via its cold nature and dries dampness via its bitterness, hence it governs these conditions. However, these are all excess diseases where righteous qi is not yet damaged and internal heat-toxin is abundant; they may be used temporarily, otherwise, one should not risk trial.

Generally, drying herbs are invariably hot; and cold herbs are invariably damp. Huangbai, while clearing heat, also possesses the effect of drying dampness.