The source is from the hooked vine of Uncaria rhynchophylla (Miq.) Jacks., family Rubiaceae. The medicinal material is mainly produced in the provinces of Hunan, Fujian and Guangdong, collected in spring and autumn, dried in the sun and cut into segments. The crude is used.

Medicinal Properties: Sweet in flavor, slightly cold in nature and attributive to the liver, heart and pericardium meridians.

Actions: Stop endogenous wind to relieve convulsion, and clear away liver-heat and calm the liver.

Application
1. It is used for liver-wind stirring inside with convulsion.  For infantile convulsion,  high fever and coma, it is combined with Tianma (Rhizoma Gastrodiae ), Shijueming ( Concha Haliotidis ), and Quanxie (Scorpio), such as Gouteng Yin (Decoction); for seasonal febrile disease with overabundance of heat bringing about wind syndrome, it is combined with Lingyangjiao ( Cornu Saigae Tataricae ), Longdan ( Radix Gentianae), and Juhua (Flos Chrysanthemi), etc.; for convulsion and cry of epilepsy, used with Tianzhuhuang ( Concertio Silicea Bambusae), Chantui (Periostracum Cicadae) and Huanglian (Rhizoma Coptidis), etc., such as Gouteng Yinzi (Decoction).
2. For liver-meridian heat syndrome manifested as distention of head, headache and redness of eyes or hyperactivity of liver-yang with dizziness, it is usually combined with Xiakucao ( Spica Prunellae), Huangqin (Radix Scutellariae ), Juhua ( Flos Chrysanthemis ) and Shijueming ( Concha Haliotidis), etc. so as to clear away heat and calm the liver.

Besides, it has good effect of lowering the blood pressure, so it can be used to treat hypertension.

Notes: 3- 12 g is used in decoction for oral use, but it is not suitable to be decocted for a long time.