Herb

Hai Tong Pi

Erythrina bark | 海桐皮

Also known as:

Ci Tong Pi (刺桐皮)

Hai Tong Pi

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Properties

Wind-Damp dispelling herbs (祛风湿药) · Neutral

Traditionally supports*

Joint and Muscle Health Lower Back and Knee Health Skin Conditions Mobility and Flexibility

Parts Used

Bark (皮 pí / 树皮 shù pí)

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

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About This Herb

Traditional Chinese Medicine background and properties

Herb Description

Erythrina bark is a traditional herb used primarily for joint and muscle pain caused by Wind and Dampness, particularly in the lower back, hips, and knees. It helps open blocked meridian pathways to relieve stiffness, numbness, and cramping. Applied topically, it also treats stubborn skin conditions like ringworm and scabies.

Herb Category

Wind-Damp dispelling herbs (祛风湿药) Wind-Damp-Heat clearing herbs (祛风湿热药)

Main Actions

  • Dispels Wind-Dampness
  • Unblocks the Channels and Collaterals
  • Alleviates Pain
  • Kills Parasites and Stops Itching

How These Actions Work

'Dispels Wind-Dampness' means Hǎi Tóng Pí drives out the Wind and Dampness that invade the joints, muscles, and meridians, causing pain and stiffness. It is especially suited to conditions of the lower body, including the lower back, hips, and knees. Its bitter taste dries Dampness while its pungent taste disperses Wind, and its neutral temperature means it can be used for both Cold-type and Heat-type blockage patterns without pushing the body further toward either extreme.

'Unblocks the channels and collaterals' refers to this herb's ability to restore the smooth flow of Qi and Blood through the body's meridian pathways. When Wind, Dampness, or Blood stasis obstruct these pathways, numbness, cramping, or restricted movement can result. As the Ben Cao Gang Mu noted, this herb "enters the Blood level and reaches the site of disease through the channels," making it particularly useful for deep-seated joint and sinew problems, as well as traumatic injuries where circulation has been disrupted.

'Kills parasites and stops itching' describes its external application for skin conditions such as scabies and fungal infections (tinea/ringworm). Laboratory studies have confirmed that Hǎi Tóng Pí water extracts show antifungal activity against several common dermatophytes. It is typically used as a topical wash or tincture rather than taken internally for these skin conditions.

Patterns Addressed

In TCM, symptoms cluster into recognizable patterns of disharmony that reveal what's out of balance in the body. Hai Tong Pi is traditionally associated with these specific patterns.

The following describes this herb's classification within Traditional Chinese Medicine theory and is provided for educational purposes only.

Why Hai Tong Pi addresses this pattern

Hǎi Tóng Pí directly targets the core pathomechanism of Wind-Damp Bi (blockage) syndrome. Its bitter taste dries Dampness while its pungent taste disperses Wind from the channels and collaterals. Entering the Liver channel (which governs the sinews), it is particularly effective at relieving joint and sinew obstruction in the lower body. Its neutral temperature makes it versatile for both Cold-predominant and Heat-predominant presentations of Bi syndrome, unlike herbs that strongly warm or cool.

A practitioner would look for one or more of these signs

Moving Pain

Especially in the lower back, hips, and knees

Joint Stiffness

Difficulty bending and extending the limbs

Numbness In The Limbs

Numbness or heaviness in the legs

Muscle Spasm

Cramping or contracture of the lower extremities

TCM Properties

Temperature

Neutral

Taste

Bitter (苦 kǔ), Acrid / Pungent (辛 xīn)

Channels Entered
Liver Kidneys
Parts Used

Bark (皮 pí / 树皮 shù pí)

This is partial information on the herb's TCM properties. More detailed information is available on the herb's dedicated page

Product Details

Manufacturing, supplier, and product specifications

Product Type

Granules

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Botanical & Sourcing

Quality Indicators

Good quality Hai Tong Pi bark comes in half-tubular or flat plate-shaped pieces, approximately 30-60 cm long and 1-2 mm thick. The outer surface should be gray-brown or gray-black with sparse longitudinal fissures and relatively dense yellowish lenticels. The most distinctive feature is the presence of large, thorn-like spines (nail-like prickles) on the outer bark surface, which is why it is also called 'Ding Tong Pi' (Nail Tong Bark). Pieces with more spines are considered better quality. The inner surface should be yellowish-brown to reddish-brown, smooth with fine longitudinal striations. The texture is hard yet tough, splitting easily lengthwise but difficult to break crosswise. The cross-section is yellowish-white to pale yellow and fibrous. It has a faint, slightly fragrant aroma and a bitter taste. Avoid pieces that are excessively thick, lack spines, or show signs of insect damage or mold.

Primary Growing Regions

The primary producing regions are Guangxi, Yunnan, and Hubei provinces in southern China. The tree is also found across Guangdong, Fujian, Zhejiang, Taiwan, Hunan, Sichuan, and Guizhou. Sichuan province is also a notable commercial source. Due to the widespread distribution of Erythrina variegata in tropical and subtropical zones, there is no single strongly defined 'dao di' (terroir) region, though Guangxi and Yunnan material is generally considered standard.

Harvesting Season

Can be collected year-round, but spring is preferred for easier bark stripping. Bark is typically harvested in summer and autumn after approximately 8 years of tree growth.

Supplier Information

Treasure of the East

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Miscellaneous Info

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Usage & Safety

How to use this herb and important safety information

Important Medical Disclaimer

The information provided here is for educational purposes only and is not intended as medical advice or to replace consultation with a qualified healthcare professional. This herb is a dietary supplement and has not been evaluated by the FDA. It is not intended to diagnose, treat, cure, or prevent any disease.

Always consult with a qualified healthcare provider, particularly if you are pregnant, nursing, have a medical condition, or are taking other medications. Discontinue use and consult your healthcare provider if you experience any adverse reactions.

Recommended Dosage

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Instructions for safe storage and consumption

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Traditional Dosage Reference

Standard

6-15g

Maximum

Up to 15g in decoction for internal use. For external use (washes, soaks, topical applications), larger amounts can be used as appropriate.

Notes

For Wind-Dampness impediment pain of the lower limbs, the standard internal dose is 6-12g in decoction, often combined with herbs like Niu Xi, Yi Yi Ren, and Wu Jia Pi. The herb may also be steeped in medicinal wine (药酒) for rheumatic conditions, where its channel-opening properties are enhanced by the alcohol medium. For external applications (scabies, eczema, fungal skin infections), a stronger decoction is prepared for washing or the powdered bark is mixed with a carrier for topical application. When used externally, the quantity is adjusted to the area being treated. Some classical sources cite doses around 9-15g (3-5 qian in traditional measures).

Processing Methods

Processing method

The bark is cleaned, cut into small pieces, then dry-fried (stir-fried without additives) until slightly darkened.

How it changes properties

Stir-frying moderately reduces the bitter-dispersing quality and makes the herb gentler on the Stomach. The thermal nature remains neutral. This form is considered slightly milder for internal use.

When to use this form

When the raw herb is too harsh for patients with a sensitive digestive system, or for general internal decoction use. The raw (unprocessed) form is preferred for topical applications.

Toxicity Classification

Non-toxic

The bark of Erythrina variegata contains multiple alkaloids, including erythraline, erysodine, erysotrine, erysovine, and hypaphorine. The Erythrina alkaloid family is known to possess curare-like neuromuscular blocking activity at high doses, particularly when the alkaloids are concentrated from seeds rather than bark. However, at standard oral decoction doses (6-15g of bark), these alkaloids are present in very low concentrations and are poorly absorbed through the gastrointestinal tract, making clinically significant toxicity unlikely. Classical Chinese sources (Hai Yao Ben Cao, Kai Bao Ben Cao) classify it as 'non-toxic' (无毒). No serious adverse reactions have been reported at prescribed doses. The seeds contain higher alkaloid concentrations than the bark and should not be confused with the medicinal bark.

Contraindications

Caution

Blood deficiency (血虚) conditions. Classical sources consistently warn that those with Blood deficiency should not take Hai Tong Pi, as it is a Wind-Dampness dispelling herb that relies on sufficient Blood to function properly. Using it in Blood-deficient patients may worsen dryness and fail to address the root cause.

Caution

Blood deficiency generating internal Wind (血虚生风). When apparent Wind symptoms actually arise from Blood deficiency rather than external pathogenic factors, Hai Tong Pi's Wind-dispelling action is inappropriate and may aggravate the condition. As the Ben Cao Qiu Zhen states, if Wind arises from internal causes, this herb should not be recklessly used.

Caution

Blood deficiency with Heat from deficiency (血少火炽). When there is insufficient Blood combined with deficiency Fire, Hai Tong Pi's drying, Wind-dispersing nature may further deplete Yin and Blood, worsening the Heat signs.

Avoid

Known allergy to Erythrina species or related Fabaceae family plants. Individuals with hypersensitivity should avoid use.

Special Populations

Pregnancy

Use with caution during pregnancy. Hai Tong Pi's Wind-dispelling and channel-opening properties, along with its ability to enter the Blood level and invigorate circulation, raise theoretical concerns about promoting unwanted uterine activity. The bark also contains Erythrina alkaloids, which have known neuromuscular and CNS effects. While no specific studies have been conducted on its reproductive toxicity, the combination of Blood-moving action and alkaloid content makes cautious avoidance the prudent approach. Consult a qualified practitioner before use during pregnancy.

Breastfeeding

No specific safety data exists for Hai Tong Pi use during breastfeeding. The bark contains Erythrina alkaloids (erythraline, erysodine, etc.) which have known CNS and neuromuscular effects. Whether these compounds transfer into breast milk at clinically relevant concentrations is unknown. Given this uncertainty, it is advisable to avoid use during breastfeeding or to use only under the supervision of a qualified practitioner who can weigh the clinical necessity against potential risk to the nursing infant.

Pediatric Use

No specific pediatric dosage guidelines are established in classical or modern sources. Given the alkaloid content of the bark, use in children should be approached cautiously and only under qualified practitioner supervision. Dosage should be reduced proportionally based on age and body weight. External use (as a wash for skin conditions) may be more appropriate for children than internal use.

Drug Interactions

No well-documented pharmaceutical drug interactions have been established through clinical studies. However, theoretical caution is warranted in the following situations:

  • Neuromuscular blocking agents: Erythrina alkaloids have demonstrated curare-like neuromuscular blocking activity in pharmacological studies. Although this effect is minimal at standard oral doses of the bark, concurrent use with neuromuscular blocking drugs (used in anesthesia) should be avoided as a precaution.
  • CNS depressants and sedatives: Preclinical research has shown that Erythrina variegata bark extract has sedative and anxiolytic properties, and may inhibit monoamine oxidase (MAO). Concurrent use with sedatives, anxiolytics, or antidepressants (especially MAO inhibitors) may theoretically produce additive effects.
  • Potassium iodide: Some TCM sources caution against concurrent use with potassium iodide, though the pharmacological basis for this interaction is not well-documented.

Dietary Advice

When taking Hai Tong Pi for Wind-Dampness conditions, avoid cold and raw foods that may generate or worsen Dampness, such as iced drinks, raw salads, and excessive dairy. Greasy, deep-fried foods should also be limited as they may impede the herb's Dampness-resolving action. Moderate consumption of mildly warming foods that support circulation is beneficial. If using the herb in a medicinal wine preparation, avoid mixing with other alcohol beyond the preparation itself.

Cautions & Warnings

Although this formula is typically safe for most individuals, it may cause side effects in some people. Pregnant women, nursing mothers, postpartum women, and those with liver disease should use the formula with caution.

As with any Chinese herbal remedy, it is advisable to seek guidance from a qualified TCM practitioner before beginning treatment.