Herb Whole plant / Aerial parts (全草 quán cǎo)

Feng Wei Cao

Spider brake herb · 凤尾草

Pteris multifida Poir. · Herba Pteridis Multifidae

Also known as: Jǐng Kǒu Biān Cǎo (井口边草), Fèng Huáng Cǎo (凤凰草), Jǐng Lán Cǎo (井阑草),

Feng Wei Cao is a cooling fern used in Chinese medicine primarily for conditions involving heat and dampness in the digestive and urinary systems. It is commonly used for bacterial dysentery, hepatitis, urinary tract infections, and various types of bleeding caused by heat in the blood. Because it is quite cold in nature, it is not suitable for people with a cold or weak constitution.

Category Herbs that clear Heat and resolve Toxicity (清热解毒药)
Therapeutic focus Digestive Health Urinary Health Liver Health Bleeding Disorders

TCM Properties

Temperature

Cold

Taste

Bitter (苦 kǔ), Bland (淡 dàn)

Channels entered

Large Intestine, Heart, Liver

Parts used

Whole plant / Aerial parts (全草 quán cǎo)

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Educational content • Consult qualified TCM practitioners for diagnosis and treatment

What This Herb Does

Every herb has a specific set of actions — here's what Feng Wei Cao does in the body, explained in both everyday and TCM terms

Therapeutic focus

In practical terms, Feng Wei Cao is primarily used to support these areas of health:

Digestive Health Urinary Health Liver Health Bleeding Disorders

TCM Actions

In TCM terminology, these are the specific therapeutic actions that Feng Wei Cao performs to restore balance in the body:

Clears Heat and Resolves Toxicity Drains Dampness Cools the Blood and Stops Bleeding Clears Heat and Stops Diarrhea Promotes Urination

How these actions work

'Clears Heat and resolves toxins' means Feng Wei Cao can counteract inflammatory, infectious conditions caused by what TCM calls Heat-toxin. This is why it has been widely used for bacterial dysentery, acute hepatitis, throat infections, and skin abscesses. Its bitter taste and cold nature give it a strong ability to drain Heat from the body.

'Drains Dampness' means this herb helps the body eliminate excess fluid and waste through urination. This makes it useful for urinary tract infections with painful, burning urination (called 'lin syndrome' in TCM) as well as for abnormal vaginal discharge caused by Damp-Heat settling in the lower body.

'Cools the Blood and stops bleeding' refers to its ability to address bleeding that arises when Heat enters the blood level and forces blood out of the vessels. This covers nosebleeds, blood in the urine, blood in the stool, hemorrhoidal bleeding, and abnormal uterine bleeding. By cooling the blood, it removes the driving force behind the bleeding.

Patterns Addressed

In TCM, symptoms cluster into recognizable patterns of disharmony. Feng Wei Cao is used to help correct these specific patterns.

Why Feng Wei Cao addresses this pattern

Feng Wei Cao's bitter and cold nature directly drains Heat and Dampness from the Large Intestine, one of its primary channel affiliations. When Damp-Heat lodges in the Large Intestine, it causes dysentery with bloody, mucous stools, abdominal pain, and tenesmus. Feng Wei Cao clears the Heat-toxin fueling the infection while its Dampness-draining action helps resolve the pathogenic dampness that creates the heavy, sticky quality of the stools.

A practitioner would look for one or more of these signs

Dysentery

Bloody, mucous diarrhea with urgency and straining

Abdominal Pain

Cramping abdominal pain worsened by pressure

Diarrhea

Frequent loose stools with foul smell

Commonly Used For

These are conditions where Feng Wei Cao is frequently used — but only when they arise from the specific patterns it addresses, not in all cases

Arises from: Large Intestine Dryness

TCM Interpretation

TCM understands acute dysentery as Damp-Heat invading and accumulating in the Large Intestine. The Heat component creates the inflammation, urgency, and bloody quality of the stools, while the Dampness produces the heavy, sticky, mucous character. The two pathogens bind together and obstruct the normal descending function of the intestines, creating the characteristic tenesmus (a feeling of incomplete evacuation with straining).

Why Feng Wei Cao Helps

Feng Wei Cao is bitter and cold, entering the Large Intestine channel directly. Its Heat-clearing and toxin-resolving actions target the infectious pathogen, while its Dampness-draining properties help eliminate the sticky, obstructive dampness in the gut. Clinical reports have documented its effectiveness in treating acute bacterial dysentery, with most patients showing symptom resolution within 2 to 7 days of treatment.

Also commonly used for

Enteritis

Acute gastroenteritis with diarrhea

Hematuria

Blood in the urine due to Heat

Hemorrhoids

Hemorrhoidal bleeding

Abnormal Uterine Bleeding

Uterine bleeding from Blood Heat

Nosebleeds

Epistaxis from blood-level Heat

Sore Throat

Throat swelling and pain from Heat-toxin

Leukorrhea

Abnormal vaginal discharge from Damp-Heat

Skin Burns

External application for burns and scalds

Herb Properties

Every herb has an inherent temperature, taste, and affinity for specific channels — these properties determine how it interacts with the body

Temperature

Cold

Taste

Bitter (苦 kǔ), Bland (淡 dàn)

Channels Entered

Large Intestine Heart Liver

Parts Used

Whole plant / Aerial parts (全草 quán cǎo)

Dosage & Preparation

These are general dosage guidelines for Feng Wei Cao — always follow your practitioner's recommendation, as dosages vary based on the formula and your individual condition

Standard dosage

15–60g (dried herb, in decoction)

Maximum dosage

Up to 60g of dried herb (or 120g of fresh herb) per day in decoction for acute conditions such as bacterial dysentery or hepatitis, under practitioner supervision.

Dosage notes

The standard dosage of 15-30g dried herb in decoction is used for most indications including damp-heat dysentery, urinary tract infections, and bleeding. For acute bacterial dysentery or infectious hepatitis, higher doses of 30-60g dried herb (or up to 120g fresh herb) have been used clinically. Fresh herb is preferred when available, especially for acute conditions, and can be juiced directly. For external use (burns, sores, skin conditions), appropriate amounts are applied as a poultice of crushed fresh herb or as a wash using the decoction. When using the herb for bleeding conditions, slightly lower doses may suffice.

Preparation

No special decoction handling required. The dried whole herb is washed, cut into pieces, and decocted normally. Fresh herb may be juiced directly (crushed and the juice expressed) for acute conditions such as hepatitis or dysentery. For external use on burns or wounds, the dried herb can be roasted to charcoal, ground to powder, and mixed with sesame oil for topical application.

Common Herb Pairs

These ingredients are traditionally combined with Feng Wei Cao for enhanced therapeutic effect

Ma Chi Xian
Ma Chi Xian 1:1 (Feng Wei Cao 15–30g : Ma Chi Xian 15–30g)

Both herbs are cold and clear Damp-Heat from the Large Intestine. Together they powerfully resolve Heat-toxin and stop dysentery, with Feng Wei Cao emphasizing Heat-clearing and bleeding control while Ma Chi Xian (Purslane) adds strong antimicrobial action and helps stop diarrhea.

When to use: Acute bacterial dysentery or Damp-Heat diarrhea with bloody, mucous stools, abdominal pain, and tenesmus.

Xiao Ji
Xiao Ji 2:1 (Feng Wei Cao 30g : Xiao Ji 15g)

Feng Wei Cao clears Heat and cools the Blood broadly, while Xiao Ji (Small Thistle) specifically cools Blood and stops bleeding with a particular affinity for the urinary system. Together they powerfully cool Blood Heat and arrest bleeding in the urine.

When to use: Hematuria (blood in the urine) caused by Blood Heat or Bladder Damp-Heat.

Bian Xu
Bian Xu 1:1 (Feng Wei Cao 15–30g : Bian Xu 15–30g)

Feng Wei Cao clears Heat-toxin and cools Blood while Bian Xu (Knotgrass) drains Damp-Heat from the Bladder and promotes urination. Together they comprehensively clear Heat, drain Dampness, and relieve painful urination.

When to use: Urinary tract infections with painful, burning, frequent urination, possibly with blood in the urine.

Ban Zhi Lian
Ban Zhi Lian 1:1 (Feng Wei Cao 30g : Ban Zhi Lian 30g)

Both herbs clear Heat and resolve toxins, but Ban Zhi Lian (Scutellaria barbata) adds stronger anti-tumor and blood-invigorating actions. Together they form a potent Heat-toxin clearing pair with documented use in gastrointestinal cancers.

When to use: Adjunctive support for gastrointestinal cancers (stomach cancer, colorectal cancer) as part of a larger formula.

Comparable Ingredients

These ingredients have overlapping uses — here's how to tell them apart

Bai Tou Weng
Feng Wei Cao vs Bai Tou Weng

Both herbs clear Heat-toxin from the Large Intestine and treat dysentery. However, Bai Tou Weng (Pulsatilla root) is more specific for amoebic dysentery and bloody dysentery with prominent blood, while Feng Wei Cao has broader applications including hepatitis, urinary infections, and various bleeding conditions. Bai Tou Weng is the stronger dysentery specialist; Feng Wei Cao is more versatile.

Di Yu
Feng Wei Cao vs Di Yu

Both are cold herbs that cool Blood and stop bleeding from the lower body (intestinal and uterine bleeding). Di Yu (Sanguisorba root) is primarily astringent and hemostatic, focused on stopping bleeding, while Feng Wei Cao has stronger Heat-clearing, Dampness-draining, and toxin-resolving actions. Choose Di Yu when bleeding is the main concern; choose Feng Wei Cao when Damp-Heat and infection are the primary problem with bleeding as a secondary symptom.

Bai Jiang Cao
Feng Wei Cao vs Bai Jiang Cao

Both clear Heat-toxin and drain Dampness, and both are used for intestinal and hepatobiliary infections. Bai Jiang Cao (Patrinia) is warmer in its toxin-draining action, better for intestinal abscesses and suppurative conditions, while Feng Wei Cao is colder and more suited for acute Damp-Heat dysentery, hepatitis, and concurrent bleeding.

Common Substitutes & Adulterants

Related species and common adulterations to be aware of when sourcing Feng Wei Cao

Feng Wei Cao can be confused with several related ferns. The most important distinction is from Guan Zhong (贯众), which is also sometimes called Feng Wei Cao in certain regional traditions (notably in the Ben Cao Tu Jing). Guan Zhong comes from entirely different fern families (Dryopteridaceae, etc.) and has a thick, heavy rhizome rather than the delicate fronds of Feng Wei Cao. Another possible confusion is with other Pteris species such as Pteris cretica (大叶凤尾蕨) or Pteris vittata (蜈蚣草), which share similar habitats but differ in leaf shape and size. Pteris vittata in particular is a known arsenic hyperaccumulator and should not be substituted. The authentic Feng Wei Cao (Pteris multifida) can be identified by its distinctively narrow, linear fertile pinnae, the winged rachis, and its relatively small overall size compared to other Pteris species.

Educational content — always consult a qualified healthcare provider or TCM practitioner before using any herb.

Toxicity Classification

Classical Chinese pharmacopoeia toxicity rating for Feng Wei Cao

Non-toxic

Feng Wei Cao is generally considered non-toxic. One classical source (Fujian Minjian Caoyao) described it as slightly toxic (微毒), but the modern consensus and most historical records classify it as non-toxic. A 28-day oral toxicity study of the aqueous extract in rats showed no significant adverse effects. However, as a cold-natured herb, excessive or prolonged use can injure Spleen and Stomach Yang, causing digestive discomfort, loose stools, and poor appetite in those without genuine damp-heat conditions.

Contraindications

Situations where Feng Wei Cao should not be used or requires extra caution

Caution

Cold-deficiency patterns of the Spleen and Stomach (脾胃虚寒). Feng Wei Cao is bitter and cold in nature and can further damage Spleen and Stomach Yang, worsening diarrhea from cold-deficiency rather than damp-heat.

Avoid

Deficiency-cold type dysentery or diarrhea (虚寒泻痢). This herb is specifically indicated for damp-heat dysentery. Using it for cold-type diarrhea will worsen the condition.

Caution

Yang-deficient or cold constitutions. Prolonged use or high doses may injure the body's Yang Qi, leading to cold extremities, poor appetite, and loose stools.

Caution

Excessive or prolonged use without damp-heat signs. As a strongly cold herb, it should be used symptomatically for acute heat conditions rather than as a long-term tonic.

Special Populations

Important considerations for pregnancy, breastfeeding, and pediatric use

Pregnancy

Use with caution during pregnancy. Although Feng Wei Cao is not traditionally listed among the strongly prohibited herbs for pregnancy, its cold nature and blood-cooling properties could theoretically affect the developing fetus by depleting Yang Qi and potentially disturbing blood circulation. It also has a history of folk use for uterine bleeding (崩漏), suggesting some activity on the uterus. Pregnant women should avoid this herb unless specifically prescribed by a qualified practitioner.

Breastfeeding

No specific safety data exists for use during breastfeeding. Given its cold nature and bitter taste, it could theoretically affect lactation or cause digestive disturbance in nursing infants through breast milk. Best avoided during breastfeeding unless specifically indicated and supervised by a qualified practitioner. If used, keep to the lower end of the dosage range and for short durations only.

Children

Used traditionally in children for conditions such as oral thrush (口糜) and acute dysentery, at reduced doses. Classical folk recipes mention 2-3 qian (about 6-9g) of fresh herb for children's mouth sores. For paediatric use in dysentery, sources note simply that the adult dose should be proportionally reduced. As with all cold-natured herbs, use cautiously in young children whose digestive systems are still developing. Short-term use only, under practitioner guidance.

Drug Interactions

If you are taking pharmaceutical medications, be aware of these potential interactions with Feng Wei Cao

No well-documented pharmaceutical drug interactions have been established for Feng Wei Cao in peer-reviewed clinical literature. However, based on its known pharmacological properties, the following theoretical considerations apply:

  • Anticoagulant/antiplatelet medications: The herb has blood-cooling and haemostatic properties. Its effects on bleeding could theoretically interact with warfarin, heparin, or antiplatelet drugs, though the direction of interaction is unclear.
  • Hypoglycaemic agents: Some fern-derived flavonoids have shown blood-sugar-lowering effects in preclinical studies. Patients on diabetes medications should be monitored if also taking this herb.
  • Immunosuppressants: Preclinical research suggests Feng Wei Cao may modulate immune function (enhancing IL-2 and immune cell activity). This could theoretically interfere with immunosuppressive therapy.

These are theoretical concerns based on pharmacological profiles, not confirmed clinical interactions. Patients on any regular medication should consult their healthcare provider before using this herb.

Dietary Advice

Foods and dietary considerations when taking Feng Wei Cao

While taking Feng Wei Cao, avoid cold and raw foods if the patient's digestion is already weak, as the herb's cold nature can compound digestive strain. The classical formula note from the Lu Chan Yan Ben Cao advises avoiding raw, cold, greasy, and toxic foods when using this herb for carbuncles. In folk practice for dysentery, sugar is often added to the decoction to improve palatability and reduce the bitterness. No specific food incompatibilities are documented.

Botanical Description

Physical characteristics and morphology of the Feng Wei Cao source plant

Feng Wei Cao (Pteris multifida Poir.) is a perennial fern in the family Pteridaceae, commonly known as spider brake or Chinese brake fern. It grows 30–70 cm tall from a short, stout, dark-brown rhizome densely covered with blackish-brown, linear-lanceolate scales. The fronds are clustered, with slender petioles 5–23 cm long, brownish-yellow to straw-coloured, and glabrous.

The frond blades are once-pinnately divided with 3–7 pairs of opposing or near-opposing pinnae. Fertile (spore-bearing) pinnae are narrow and linear, 3–6 mm wide, with margins rolled under to cover the linear sporangia along their edges. Sterile pinnae are broader, with irregularly serrate margins. The central leaf axis (rachis) bears a conspicuous wing. Veins are clearly visible, branching out from a central midvein in a feather-like pattern.

The plant favours shady, moist habitats and is characteristically found growing in rock crevices, beside wells, on old stone walls, and at the bases of buildings, below about 850 metres elevation. It tolerates drought reasonably well and can overwinter in temperatures down to about 5°C. It is native to central and southern China, Korea, Japan, the Ryukyu Islands, Taiwan, and Vietnam.

Sourcing & Harvesting

Where Feng Wei Cao is sourced, when it's harvested or collected, and how to assess quality

Harvesting season

Can be harvested year-round; best collected in summer and autumn when the plant is most vigorous.

Primary growing regions

Feng Wei Cao is widely distributed across southern China and does not have a single definitive dao di (terroir) production region. Major producing areas include Zhejiang, Jiangsu, Fujian, Guangdong, Guangxi, Hunan, Jiangxi, Sichuan, Guizhou, Yunnan, and Shaanxi provinces. It also grows in Taiwan. Outside China, it is native to southern Korea, Japan, the Ryukyu Islands, and Vietnam. Most commercial herb material is locally collected and sold rather than centrally traded, as the plant grows abundantly in the wild.

Quality indicators

Good quality dried Feng Wei Cao comes in small bundles of whole plants, 25-70 cm long. The rhizome should be short and brownish-brown with fine rootlets. The petioles should be brownish-yellow or yellowish-green, slender, and easily broken. The leaf blades should be greyish-green or yellowish-green, intact rather than crumbled, with a grass-like texture. Fertile leaves should show clearly visible, linear sporangia along the rolled-under leaf margins. The aroma is faint and the taste is bland or slightly astringent. Avoid material that is heavily browned, mouldy, overly fragmented, or mixed with excessive root debris.

Classical Texts

Key passages from the classical Chinese medical texts that describe Feng Wei Cao and its therapeutic uses

《中药学》(Textbook of Chinese Materia Medica)

Original: 本品有清热利湿之功，用于痢疾、腹泻...本品功能凉血解毒，用于咽喉肿痛，尿血，便血，痔疮出血。

Translation: "This substance has the function of clearing heat and draining dampness, used for dysentery and diarrhea... it functions to cool the Blood and resolve toxins, used for sore throat, blood in the urine, blood in the stool, and haemorrhoidal bleeding."

《履巉岩本草》(Lǚ Chán Yán Běn Cǎo, Southern Song Dynasty, c. 1220)

Original: 治五毒发背：小金星凤尾和根，洗净，用慢火焙干，称四两，入生甘草一钱。捣末分作四服。

Translation: "For treating the five types of toxic back carbuncles: Take 'Small Gold Star Phoenix Tail' [Feng Wei Cao] with its root, wash clean, dry slowly over gentle fire, weigh four liang, add one qian of raw Gan Cao. Pound into powder and divide into four doses."

《生草药性备要》(Shēng Cǎo Yào Xìng Bèi Yào)

Original: 味辛，性平。

Translation: "Flavour: acrid; nature: neutral." (This represents an early characterisation that differs from the modern consensus of bitter and cold.)

Historical Context

The history and evolution of Feng Wei Cao's use in Chinese medicine over the centuries

Feng Wei Cao (凤尾草, "Phoenix Tail Grass") takes its name from the graceful, feather-like arrangement of its pinnae, which are said to resemble the tail feathers of a phoenix. It has accumulated a remarkable number of folk names across different regions of China, reflecting its widespread use in rural medicine. These include Jǐng Kǒu Biān Cǎo (井口边草, "grass beside the well mouth"), Jīn Jī Wěi (金鸡尾, "golden rooster tail"), and Jī Jiǎo Cǎo (鸡脚草, "chicken foot grass"), all describing either its appearance or its preferred habitat near wells and stone walls.

The earliest known recorded name for this herb is Jǐng Kǒu Biān Cǎo, which appeared in the Tang Dynasty text Běn Cǎo Shí Yí (本草拾遗, Omissions from the Materia Medica) by Chén Cáng Qì. The Southern Song Dynasty local herbal Lǚ Chán Yán Běn Cǎo (履巉岩本草, c. 1220 CE) recorded it under the name "Small Gold Star Phoenix Tail" (小金星凤尾) for treating toxic carbuncles and hair loss. The name Feng Wei Cao itself became established in the Qing Dynasty through Zhí Wù Míng Shí Tú Kǎo (植物名实图考, Illustrated Investigation of Plant Names and Facts) by Wú Qí Jùn.

Feng Wei Cao has long been a mainstay of folk medicine throughout southern China, particularly valued for treating acute bacterial dysentery and infectious hepatitis. During the mid-20th century, clinical reports documented its use in treating large numbers of dysentery patients with good results, cementing its reputation as a reliable heat-clearing and damp-draining herb accessible to rural populations.

Modern Research

5 published studies investigating the pharmacological effects or clinical outcomes of Feng Wei Cao

1

Antitumour Effect of Total Flavonoids from Pteris multifida in H22 Tumour-Bearing Mice (Preclinical, 2013)

Dai GC et al., African Journal of Traditional, Complementary and Alternative Medicines, 2013, 11(2), 481-485

This animal study investigated total flavonoids extracted from Feng Wei Cao in mice bearing H22 liver tumours. The high-dose group showed a tumour inhibition rate of about 49%, and the treatment improved immune markers (IL-2, TNF-alpha) and antioxidant capacity in the mice, suggesting the anti-tumour mechanism may involve both immune enhancement and antioxidant activity.

PubMed
2

Cytotoxic Pterosins from Pteris multifida Roots Against HCT116 Human Colon Cancer Cells (Preclinical, 2017)

Kim JW, Kim HP, Sung SH, Bioorganic & Medicinal Chemistry Letters, 2017, 27(14), 3144-3147

Researchers at Seoul National University isolated twelve pterosin-type sesquiterpenoids from Feng Wei Cao roots. One newly discovered pterosin glycoside showed moderate anti-cancer activity against human colon cancer cells (HCT116) with an IC50 of 8.0 μM, inducing cell death via the caspase-9 apoptosis pathway.

Link
3

Chemical and Biologically Active Constituents of Pteris multifida (Phytochemical study, 2008)

Harinantenaina L, Matsunami K, Otsuka H, Journal of Natural Medicines, 2008, 62(4), 452-455

This study identified 13 compounds from Feng Wei Cao, including flavonoid glycosides (apigenin and luteolin glucosides as major constituents), pterosin sesquiterpenoids, and caffeoylquinic acids. Several pterosin compounds showed significant selective cytotoxicity against KB cancer cells.

Link
4

Pteris multifida, Cortex Phellodendri, and Probiotics Attenuated Inflammatory Status and Immunity in Mice with Salmonella Infection (Preclinical, 2018)

Yin MC, Chang CH, Su CH, Yu B, Hsu YM, Bioscience, Biotechnology, and Biochemistry, 2018, 82(5), 836-847

In mice infected with Salmonella Typhimurium, aqueous extract of Feng Wei Cao reduced bacterial counts in the blood, intestine, and liver. It also lowered TNF-alpha and IL-1beta inflammatory markers in serum, suggesting anti-inflammatory and anti-Salmonella effects.

Link
5

Cytotoxic Diterpenoids and Sesquiterpenoids from Pteris multifida (Phytochemical study, 2008)

Ge X, Ye G, Li P, Tang WJ, Gao JL, Zhao WM, Journal of Natural Products, 2008, 71(2), 227-231

Six new compounds were isolated from Feng Wei Cao, including three ent-kaurane diterpenoids and three new pterosin sesquiterpenoids. Two compounds showed cytotoxicity against HepG2 liver cancer cells with IC50 values below 10 μM, supporting the herb's traditional use in cancer-related formulas.

Link

Research on individual TCM herbs is growing but still limited by Western clinical trial standards. These studies provide emerging evidence and should be considered alongside practitioner expertise.