Uncaria rhynchophylla or the cat's claw herb is a plant species used in traditional Chinese medicine. (+)-Catechin and (-)-epicatechin are found in the plant as well as the alkaloid rhynchophylline.
Woody vines or lianas, climbing by recurved, usually paired spines generally 1-2 cm. Raphides absent. Leaves opposite, usually with domatia; stipules persistent or caducous, interpetiolar, generally ovate to ligulate in outline, entire to 2-lobed, usually reflexed. Inflorescences axillary and sometimes also terminal, capitate with heads globose and 1 to several in cymes or fascicles, pedunculate, bracteate; peduncles usually articulate in middle or upper portion, often with stipuliform bracts at articulation; bracts enclosing heads sometimes caducous, involucral, stipuliform. Flowers sessile and bracteolate or pedicellate and bracteolate or ebracteolate, bisexual, monomorphic. Calyx limb 5-lobed. Corolla white to yellow, salverform or funnelform, inside glabrous or pubescent; lobes 5, imbricate in bud.