Guan Chong

Guan Chong is most often derived from Dryopteris crassirhizoma (Dryopteridaceae) and, in some southern Chinese regions, from Cyrtomium fortunei (holly fern). Both are terrestrial perennial ferns of moist forest floors and shaded slopes. Dryopteris crassirhizoma forms a stout, ascending, scaly rhizome up to 20 cm long and 4–7 cm thick, crowned by a dense rosette of bipinnate fronds 50–100 cm long with chaffy stipes. Cyrtomium fortunei is smaller, with pinnate fronds bearing leathery, sickle-shaped pinnae. The medicinal organ in both is the dried rhizome, often retaining the persistent dark brown leaf-base remnants and reddish-brown ramentum. The rhizome contains phloroglucinol derivatives (filicin complex) responsible for both the anthelmintic activity and the inherent toxicity that requires cautious dosing.