Guan Zhong (Wood Fern or Dryopteris)

Guan Zhong is also known as Wood Fern, Male Fern, Buckler Fern or Dryopteris, which is one of the earliest medicines discovered and applied in traditional Chinese herbal medicine. It has a medicinal history of more than 2,000 years.

Dryopteris is a large genus of the family Dryopteridaceae. There are more than 400 species in this genus, which are distributed in Asia, Europe, America, and the Pacific islands.

The Guan Zhong referred to herein is the rhizome of Dryopteris crassirhizoma. It is mainly produced in Heilongjiang, Jilin, and Liaoning of China.

In the autumn of each year, people gather the rhizomes of Dryopteris, wash them with water, remove their impurities and fibrous roots, cut them into thick pieces, dry them in the sun, and make them into Chinese herbs.

Guan Zhong contains aspidin, albaspidin, filicic acid, flavaspidic acid, dryocrassin, isoquercitrin, astragalin, catechinic acid, daidzein, triterpenoids, steroids, caffeic acid, glycosides, and volatile oils. Generally, Guan Zhong with yellowish-brown or black-brown outer epidermis and light brown or reddish-brown cross-section is the best.

According to <Shennong Ben Cao Jing>, the medicinal property of Guan Zhong is slightly cold, with slight toxicity and bitter taste. It has a certain therapeutic effect on the pathological changes of the liver and spleen meridians.

In Chinese medicine, Guan Zhong is often used to clear heat and remove toxin, cool blood and stop bleeding, kill worms, treat wind-heat, influenza, upper respiratory tract infection, ascariasis, acute orchitis, upper gastrointestinal bleeding, drug-induced hepatitis, and gynecological bleeding.

There are about 50 kinds of traditional Chinese medicine prescriptions containing Guan Zhong, such as Lianhua Qingwen capsule, Fu Fang Qing Dai Wan, and Da Huo Luo Dan.

Health benefits of Guan Zhong

  • Anti-oxidation, anti-malaria, and anti-tumor.
  • Inhibiting leukemia cells and exciting the uterus.
  • Relieving fever, headache, nasal obstruction, and sore throat caused by wind-heat.
  • Clearing heat and eliminating maculae caused by warm toxins.
  • Cooling blood and relieving hematemesis, epistaxis, and hematochezia caused by blood heat.
  • Treating leukorrheal diseases, menorrhagia, postpartum lochia, and metrorrhagia.
  • Inhibiting influenza virus, parainfluenza virus, avian influenza virus, respiratory syncytial virus, adenovirus, poliovirus, and Japanese encephalitis virus.
  • Inhibiting dysentery bacilli, typhoid bacilli, Escherichia coli, Proteus, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, and some skin fungi.
  • It contains filicic acid and flavaspidic acid, which can expel a variety of intestinal parasites, such as tapeworms, hookworms, pinworms, roundworms.
  • The topical application of it can treat burns and scalds, with hemostasis, analgesia, anti-inflammatory effects.

Guan Zhong is used with other Chinese herbs

  • It can be combined with Huang Lian (Rhizoma Coptidis) to treat epistaxis caused by blood heat.
  • It with Sang Ye (Mulberry Leaf) and Jin Yin Hua (Flos Lonicerae) can prevent and treat fever, headache, nasal obstruction, and sore throat caused by wind-heat.
  • It with Yu Mi Xu (Corn Silk) and Bai Mao Cen (Rhizoma Imperatae) can treat chyluria.
  • It with Chuan Shan Jia (Squama Manitis), Zhen Zhu (Pearl), and Bing Pian (Borneol) can treat newborn omphalitis.
  • It with Bi Xie (Rhizoma Dioscoreae Hypoglaucae), Dang Shen (Radix Codonopsis), and Ji Xue Teng (Caulis Spatholobi) can treat chronic lead poisoning.

Side effects of Guan Zhong

Guan Zhong is poisonous, and some countries stipulate that it can only be used for external use.

Taking it in large doses may cause headache, dizziness, abdominal pain, diarrhea, dyspnea, yellow vision, or transient blindness.

In severe cases, it may cause delirium, coma, jaundice, renal impairment, paroxysmal convulsions, respiratory failure, permanent blindness, or death.

Precautions of Guan Zhong

  • The dosage of Guan Zhong should be controlled between 4.5-9g.
  • It can be made into decoction or ground into powder for external use.
  • The unprocessed Guan Zhong recommended for clearing heat and removing toxins, and the carbonized Guan Zhong recommended for stopping bleeding.
  • Fat can promote the body’s absorption of aspidin, so it is not recommended to eat greasy foods during medication.
  • It should not be used to clear internal heat caused by Yin deficiency.
  • Pregnant and lactating women should not take it.
  • Children should take it under the guidance of doctors.
  • People with deficiency-cold in spleen and stomach should not take it.
  • People with weak constitutions, liver and kidney dysfunction, or peptic ulcers should not take it.

Treatments of Guan Zhong poisoning

  • Taking a general antidote to alleviate poisoning.
  • Infusion is recommended to supplement body fluids and electrolytes lost due to vomiting or diarrhea.
  • Taking salt laxatives to promote the excretion of poisons from the intestine. It is not recommended to use oily laxatives such as castor oil.
  • Intravenous barbiturates can relieve convulsions during medication.
  • When breathing difficulties occur during medication, it is recommended to supply oxygen, use respiratory stimulants or artificial respiration.