Adjunct in Xiao Yao San

Bò He 薄荷

Chinese mint · Menthae Haplocalycis Herba (Mentha haplocalyx) · small amount, added late in the classical formula

Role in the formula

Bò he is used in a small amount, added late — a finishing touch rather than a foundation. Its aromatic lightness gives the constrained liver qi somewhere to go, dispersing the stagnant heat that constraint generates. The image in the commentaries is of opening a window in a stuffy room^[1].

Character

Acrid, aromatic, and cooling, entering the lung and liver channels. Elsewhere in the pharmacopoeia bò he releases wind-heat at the exterior, benefits the throat and eyes, and vents rashes; its liver-soothing role in Xiao Yao San is its most famous supporting part^[1].

In the pharmacy

The aerial parts of Mentha haplocalyx — a true field mint. Because its volatile oils are the point, it is added in the final minutes of a decoction, never boiled long.