Deputy in Xiao Yao San

Dāng Guī 当归

Chinese angelica root · Angelicae Sinensis Radix (Angelica sinensis) · 30 g in the classical formula

Role in the formula

Dāng guī serves as deputy. Where chái hú moves what is stuck, dāng guī replenishes what the movement draws on: the blood the liver is said to store. Its double action — nourishing blood while also invigorating its flow — is why it, rather than a purely tonic herb, partners the chief^[1].

Character

Sweet, acrid, and warm, entering the liver, heart, and spleen channels. Dāng guī is the tradition's signature herb for the blood: it tonifies, invigorates, regulates menstruation, and moistens^[1]. Its prominence in gynecology is one reason Xiao Yao San became so closely associated with menstrual and premenstrual complaints.

In the pharmacy

The root of Angelica sinensis, grown chiefly in Gansu province, with a distinctive sweet-pungent aroma. 30 g in the classical proportions.