Ban Lan Gen, the root of indigo
Ban Lan Gen reads “the root of the board indigo”, and the name says it all: this plant was first a dye plant. Its leaves give indigo blue, and it was grown for dyeing for centuries before its uses in the pharmacopoeia gradually emerged. It is also known as woad and isatis: Isatis indigotica, syn. Isatis tinctoria, a biennial of the cabbage family with small, yellow, cross-shaped flowers. Its taproot is used, dug up in autumn after the leaves have been cut two or three times over the summer. Its reference growing region is the North: Hebei, Shandong and Inner Mongolia. When cut, a good root shows a solid wood of a clear yellow.
Clearing Heat, with no detours
In traditional Chinese medicine, the root is cold and bitter: bitterness makes things descend, cold clears Heat, and there is nothing else in this profile, which makes it a straightforward substance. It enters the Heart, which tradition holds to be the master of the Blood, and the Stomach. Its primary action is to clear a Heat that tradition calls fierce, one that moves fast and strikes hard, and to undo its fierceness. Through the Heart, it also cools the Blood when Heat has entered it. That is the flip side of its frankness: a substance of this temperament has no place where Cold dominates.
The root that descends, the leaf that disperses
The same plant provides three substances: the root, the leaf, Da Qing Ye, and the indigo pigment. A classical author summed up their difference in one sentence: “the leaf governs dispersal, and the root governs descent”. Tradition chooses the root when the matter plays out in the upper body, and the leaf when it plays out in the Blood. With figwort, which moistens, it forms a classic pair when the Fluids are lacking. Gentler on digestion than some neighbouring roots, it remains a herb for short-term use.
Key benefits
Heat cleared & frankness
Bitter and cold, isatis root clears Heat according to Chinese tradition, adding nothing else.
Frank & soothing coolness
A root that makes things descend, it cools and soothes, with a frank coolness that tradition reserves for warm constitutions.
Coolness & Blood cooled
Through the Heart, master of the Blood, it cools and soothes feelings of warmth.
