An Introduction to the Benefits, Uses and Plant Morphology of Cayratia tetragona

Cayratia tetragona is the dried vine stem of the four-angled treebine (Cayratia tetragona), a plant in the grape family Vitaceae, genus Cayratia. It gets its name because the cross-section of the stem is roughly square with four distinct ridges, and among the general public it is also often known by other names such as Sifang Kuanjin Teng. It is mainly distributed in the warm-climate regions of South China and Southwest China, and is commonly found under forest in valleys, at the edges of thickets, or in rock crevices beside streams, where it climbs over trees and rock faces by means of tendrils.

In appearance, Cayratia tetragona is a perennial woody climbing vine; its stems and branches are distinctly four-angled and often bear narrow wings, with slightly swollen nodes and a tough texture. The leaves are mostly simple and alternate, roughly ovate or ovate-elliptic in shape, with edges that often bear sparse fine teeth. In the flowering season it produces small pale flowers, with cymes opposite the leaves, and the fruit is a spherical berry whose skin darkens noticeably when ripe.

In terms of practical value, Cayratia tetragona is one of the Chinese herbal medicines commonly used by the general public in southern regions. It is traditionally believed to dispel wind and remove dampness and to relax the sinews and invigorate the collaterals, and it is mostly used as supportive care for rheumatism and bone pain, poor joint movement, soreness and aching of the lower back and legs, and traumatic injuries. Common methods of use include decocting it in water for oral intake, steeping it in liquor, or pounding it into a paste for external application. It must be stressed that the specific dosage and herbal combinations should be carried out under the guidance of a physician or pharmacist, and it should not be used blindly on one's own.

It should also be noted that the plants referred to by local common names such as Kuanjin Teng and Shujin Teng are not entirely the same, so when purchasing one should carefully verify the source and external characteristics of the medicinal material to avoid mixing them up or using the wrong one. In addition, differences in harvest season and place of origin affect the quality of the medicinal material, and for daily storage it is best to keep it in a ventilated, dry place to prevent dampness and mould, so as to ensure its effectiveness.