Shield Fern Rhizome Pieces (Dryopteris Crassirhizoma)

Shield Fern Rhizome Pieces (Dryopteris crassirhizoma) are the dried rhizome sections of a traditional fern used in Traditional Chinese Medicine (TCM) known as Guàn Zhòng (贯众). This herb has a long history of use for its heat-clearing, toxin-resolving, parasite-expelling, and bleeding-stopping properties, particularly in conditions involving intestinal parasites, epidemic heat, sore throat, and blood heat disorders. Its nature is bitter and cold, giving it a strong downward-clearing and detoxifying action.

In TCM, Guan Zhong enters the Liver, Stomach, and Large Intestine channels, where it helps clear heat and fire toxin, cool the blood, stop bleeding, and expel parasites. It is traditionally used for roundworm and tapeworm infestations, dysentery, bloody stools, nosebleeds, vomiting blood, and uterine bleeding caused by heat, as well as for throat swelling, mumps, and epidemic febrile diseases. Its ability to cool blood heat makes it especially valuable in formulas addressing toxic heat attacking the blood level.

Historically, Shield Fern Rhizome was also used during outbreaks of infectious or epidemic illnesses, taken as a decoction to clear internal heat, reduce toxicity, and protect against transmission, reflecting its strong antimicrobial and detoxifying reputation in classical texts.

Modern research shows that Dryopteris crassirhizoma contains phloroglucinols, flavonoids, tannins, and antimicrobial compounds with documented antiparasitic, antiviral, antibacterial, anti-inflammatory, and hemostatic effects. These constituents support its traditional use for parasite expulsion, infection-related heat, and bleeding due to heat toxin.

Each batch of Shield Fern Rhizome Pieces (Dryopteris crassirhizoma) is carefully harvested, sliced, and dried to preserve its dense texture, dark coloration, and potent bitter-cooling character. When decocted, it produces a strong, bitter, cooling infusion traditionally used to clear heat toxin, expel parasites, cool the blood, and stop bleeding.