Gou Teng, the vine with paired hooks

Gou Teng simply reads “hooked vine”. At each node of its stem, this large woody vine of the coffee family bears two hooks curving downwards like fish hooks, which it uses to cling to trees; these hooks make up the substance, and the paired hooks are its mark of authenticity. It grows in the humid, shady forests of southern China, in Guangxi, Guizhou, Hunan and Fujian, and is harvested in autumn and winter. Its history is unusual: for a thousand years it was used only for children, before becoming one of the great Liver plants.

Calming the Liver, without harshness

In Traditional Chinese Medicine, Gou Teng is cool and sweet: sweetness relaxes and moderates, coolness tempers, with no bitterness that forces nor pungency that disperses. It enters the Liver and the Pericardium, and Li Shizhen drew an image from this: it links one to the other, and “the Wind settles, the Fire dies down”. Tradition credits it with calming the Liver and gently bringing its Yang back down when it rises in excess, the action for which it is most used today, and with clearing a moderate Heat of the Liver. Its sweetness also loosens what is tense.

Moderation, and the rule of the end

Its own character is moderation: other substances quench Wind or clear Heat more strongly, but it does both at once, and without harshness. With chrysanthemum, which clears Liver Heat and brightens the eyes, it forms a pair in equal parts. One rule matters above all: it goes in at the end of the decoction, for the last five to fifteen minutes, because its active compounds, indole alkaloids, break down after about twenty minutes of boiling. Modern research is particularly interested in rhynchophylline.