Thick-stemmed wood fern

The first day or two of an influenza-like illness in an epidemic season, with fever, sore throat and a red tongue, in an adult who is otherwise robust

Heavy, bright-red menstrual bleeding in a woman with heat signs, where the charred rhizome is added to a blood-cooling formula for a few days

Overview. Mian ma guan zhong is the thick, dark, scale-covered rhizome of a large wood fern of the cool forests of northeast China, Korea, Japan and the Russian Far East. Several unrelated ferns are traded as 'guan zhong'; this species is the pharmacopoeial one. It is the East Asian counterpart of the European male fern and shares its acylphloroglucinol chemistry, which explains both its worm-killing history and its toxicity. Chinese medicine uses it in small doses to clear heat and toxin in epidemic disease, to expel parasites, and, charred, to stop bleeding.

Clinical Notes. Use guan zhong as a short, low-dose herb, never as a tonic. Its modern place is at the onset of an epidemic viral illness, combined with ban lan gen, jin yin hua and lian qiao, or with da qing ye and huang qin, for two to five days; many Chinese over-the-counter cold and flu formulas contain it.

Chinese Medicine Profile. Temperature: slightly cold, slightly toxic. Taste: bitter. Channels: Liver, Stomach. Actions: Clears heat and resolves toxicity in epidemic febrile disease, mumps and hot swellings; Kills intestinal parasites, the ancient anthelmintic use shared with the European male fern; Cools the blood and stops bleeding, especially when charred, in uterine bleeding, nosebleed and bloody stool; Prevents seasonal epidemic disease, the old custom of steeping the rhizome in drinking water.