Lophatherum, “the bland bamboo leaf”

Dan Zhu Ye reads “the bland bamboo leaf”: the name combines its bland flavour and its resemblance to bamboo foliage. Yet it is not a bamboo but a grass, Lophatherum gracile, whose lance-shaped leaves show a fine grid of veins on the underside. It grows wild in the shady, damp undergrowth of southern China; Zhejiang is considered the best source. The leafy stems are harvested in summer, before the spikes appear, and the root is always removed. A legend from the Three Kingdoms tells how Zhuge Liang passed off a decoction of Dan Zhu Ye as wine, drunk by soldiers overcome by the heat: the story reflects the plant’s reputation as a refreshing summer drink.

Clearing above, guiding below

In traditional Chinese medicine, the leaf is cold, sweet and bland in flavour: cold clears, blandness lets things flow, sweetness spares the Fluids. Light, it rises to clear the upper body, then guides what it has cleared downwards, through the urine. It enters the Heart and the Small Intestine, which tradition describes as paired: Heart Fire can descend to the Small Intestine, which separates the clear from the turbid, and the plant offers it a way out. Tradition thus credits it with gently clearing Heat and Heart Fire, and with promoting the flow of urine. The Ben Cao Bian Du sums it up in one formula: clear above, guide below. With raw rehmannia, it forms the core of Dao Chi San.

A freshness that restores the Fluids

It also enters the Stomach, whose Heat it clears. When Heat troubles the Heart, which houses the mind, tradition describes agitation; the plant dispels it and, at the same time, generates the Fluids that Heat consumes, hence its use to quench thirst. Li Shizhen credits it with dispelling agitating Heat and clearing the Heart. It is distinct from the true bamboo leaf, Zhu Ye, which clears the Heart more strongly but guides downwards less well. Made of light leaves, it should not be cooked for too long.