Herb Bark (皮 pí / 树皮 shù pí)

He Huan Pi

Silk tree bark · 合欢皮

Albizia julibrissin Durazz. · Cortex Albiziae

Also known as: Albizia bark, Mimosa tree bark, Persian silk tree bark,

He Huan Pi (Silk tree bark) plant

Images shown are for educational purposes only

Known as the "happiness bark" in Chinese medicine, silk tree bark is one of the most treasured herbs for lifting mood and easing emotional tension. It is traditionally used for depression, anxiety, insomnia caused by emotional distress, and to help heal injuries and reduce swelling. Its gentle, neutral nature makes it suitable for a wide range of people.

Category Spirit-calming herbs (安神药) Herbs that nourish the Heart and calm the Spirit (养心安神药)
Therapeutic focus Emotional Wellbeing Sleep Support Injury and Trauma Recovery

TCM Properties

Temperature

Neutral

Taste

Sweet (甘 gān)

Channels entered

Heart, Liver, Lungs

Parts used

Bark (皮 pí / 树皮 shù pí)

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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 He Huan Pi does in the body, explained in both everyday and TCM terms

Therapeutic focus

In practical terms, He Huan Pi is primarily used to support these areas of health:

Emotional Wellbeing Sleep Support Injury and Trauma Recovery

TCM Actions

In TCM terminology, these are the specific therapeutic actions that He Huan Pi performs to restore balance in the body:

Relieves Constraint and Calms the Spirit Invigorates Blood and Reduces Swelling Strengthens the Sinews and Bones Disperses Swelling and Dissipates Abscesses

How these actions work

'Calms the spirit and relieves depression' (安神解郁 ān shén jiě yù) is He Huan Pi's primary and most celebrated action. It works by entering the Heart and Liver channels to soothe emotional constraint and restore a sense of ease. The Shen Nong Ben Cao Jing described it as an herb that "harmonises the five organs, calms the Heart's intentions, and makes one joyful and free from worry." It is especially suited for people whose emotional distress stems from frustration, resentment, grief, or prolonged worry that has knotted the Liver Qi and disturbed the Heart spirit. Symptoms include insomnia, irritability, low mood, tearfulness, and a sense of inner restlessness. Unlike heavy sedatives (such as mineral-based substances that weigh the spirit down), He Huan Pi works gently by resolving the underlying emotional stagnation. A classical teaching notes "合欢蠲忿" (He Huan dispels resentment).

'Invigorates Blood and reduces swelling' (活血消肿 huó xuè xiāo zhǒng) means He Huan Pi can move stagnant Blood and reduce swelling from traumatic injuries. Because it enters the Blood level of the Heart and Liver channels, it can address bruising, pain, and swelling from falls, blows, or fractures. It is classically paired with herbs like frankincense (Ru Xiang) and myrrh (Mo Yao) for this purpose.

'Promotes tissue regeneration and reunites sinews and bones' (续筋接骨 xù jīn jiē gǔ) refers to He Huan Pi's traditional use in helping heal broken bones and torn sinews. The Ben Cao Yan Yi Bu Yi noted that it "supplements Yin rapidly, grows muscle tissue, and mends sinews and bones." It was applied both internally (as a decoction or powder with wine) and externally (as a poultice) for fractures.

'Disperses abscesses' (消痈 xiāo yōng) refers to its ability to resolve internal and external abscesses by moving Blood and reducing toxic swelling. It is best known for treating lung abscess (fei yong), where it was used as a single herb in the classical formula Huang Hun Tang from the Qian Jin Fang. At higher doses (30-60g), this abscess-dispersing action becomes more prominent.

Patterns Addressed

In TCM, symptoms cluster into recognizable patterns of disharmony. He Huan Pi is used to help correct these specific patterns.

Why He Huan Pi addresses this pattern

He Huan Pi directly addresses Liver Qi Stagnation by entering the Liver channel and gently unblocking constrained Qi. Its sweet taste harmonises and relaxes, counteracting the tight, knotted quality of stagnant Liver Qi. Where Liver Qi Stagnation disturbs the Heart spirit (because the Liver governs the smooth flow of emotions and Qi throughout the body), He Huan Pi simultaneously calms the Heart by entering the Heart channel. This dual action on both the Liver and Heart makes it especially effective for the emotional manifestations of Liver Qi Stagnation: irritability, frustration, sighing, and a feeling of chest oppression that worsens with emotional stress.

A practitioner would look for one or more of these signs

Depression

Low mood, melancholy, or sadness from emotional constraint

Irritability

Frustration and irritability that fluctuate with emotional triggers

Insomnia

Difficulty falling asleep due to overthinking or rumination

Chest Stiffness

Sensation of chest or rib-side tightness and oppression

Commonly Used For

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

Arises from: Liver Qi Stagnation Heart and Spirit Disturbance

TCM Interpretation

In TCM, healthy sleep depends on the spirit (Shen) being properly housed in the Heart at night. When emotions like frustration, resentment, grief, or worry persist, they cause Liver Qi to stagnate. The Liver governs the smooth flow of Qi and emotions throughout the body, so when Liver Qi becomes knotted, it directly disturbs the Heart, preventing the spirit from settling peacefully at night. This type of insomnia is characterised by difficulty falling asleep due to a racing mind, or waking during the night with a sense of unease. It is distinct from insomnia caused by Blood or Yin deficiency, which tends to involve night sweats and hot sensations.

Why He Huan Pi Helps

He Huan Pi is specifically suited for insomnia rooted in emotional disturbance because it simultaneously unblocks Liver Qi stagnation and calms the Heart spirit. Its sweet taste and neutral temperature gently relax without being sedating or heavy. By resolving the emotional constraint that is the root cause of the sleeplessness, it addresses the problem at its source rather than simply suppressing wakefulness. The Ben Cao Qiu Zhen notes that He Huan Pi's action is gentle and gradual, meaning it works best with consistent use over time rather than as a one-off sleep aid. Clinically, it is often paired with Shou Wu Teng (Caulis Polygoni Multiflori) and Suan Zao Ren (Ziziphi Spinosae Semen) to enhance its sleep-promoting effect.

Also commonly used for

Irritability

Frustration and irritability from Liver Qi constraint

Trauma

Bruising, swelling, and pain from physical trauma

Bone Fractures

Bone fractures with swelling and pain, to promote healing

Periappendiceal Abscess

Lung abscess or skin abscesses with swelling

Poor Memory

Forgetfulness associated with emotional disturbance

Mood Swings

Emotional instability, including perimenopausal mood changes

Herb Properties

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

Temperature

Neutral

Taste

Sweet (甘 gān)

Channels Entered

Heart Liver Lungs

Parts Used

Bark (皮 pí / 树皮 shù pí)

Dosage & Preparation

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

Standard dosage

6-15g

Maximum dosage

Up to 60g for treating lung abscess (肺痈) or severe infectious inflammatory conditions, under practitioner supervision. Clinical reports note use up to 90g without adverse effects.

Dosage notes

He Huan Pi is a gentle herb whose effects vary significantly with dosage, as noted in classical and clinical sources. At standard doses of around 6-10g, it primarily acts as a mild sedative and spirit-calming herb for insomnia and emotional disturbance. At moderate doses of 15-20g, its Blood-activating and swelling-reducing properties become more prominent, making it suitable for trauma, pain, and Blood stasis conditions. At higher doses of 30-60g, its ability to resolve abscesses and reduce inflammation becomes its primary action, and it has been used at these levels for lung abscess, lobar pneumonia, and pleural effusion. The classical Ben Cao Qiu Zhen specifically notes that this herb has a gentle nature and mild strength, so small doses may not produce noticeable results. For emotional and spirit-calming purposes, sustained use over time is often needed rather than short-term high doses.

Preparation

No special decoction handling is required. He Huan Pi is decocted normally with other herbs. The bark pieces should be soaked in water for 20-30 minutes before decocting to facilitate extraction of active constituents. It is used in its raw, unprocessed form (生用). For external application in treating sores and trauma, the bark is ground into powder and mixed with oil or other vehicles for topical use.

Processing Methods

In TCM, the same herb can be prepared in different ways to change its effects — here's how processing alters what He Huan Pi does

Processing method

The bark is cut into pieces and dry-fried (stir-fried without additives) until it turns slightly yellow to dark yellow, sometimes until lightly charred on the surface.

How it changes properties

Dry-frying moderates the herb's Blood-moving action and slightly warms its nature. It reduces any mild irritation to the digestive tract and enhances the herb's ability to promote tissue healing and bone reunification. The core spirit-calming property is preserved.

When to use this form

Preferred for traumatic injuries and bone fractures where the focus is on tissue regeneration rather than emotional calming. Classical formulas for fractures specifically call for the dry-fried form.

Common Herb Pairs

These ingredients are traditionally combined with He Huan Pi for enhanced therapeutic effect

Ye Jiao Teng
Ye Jiao Teng 1:1 to 1:2 (He Huan Pi 10-15g : Ye Jiao Teng 15-30g)

He Huan Pi resolves Liver Qi stagnation and lifts the spirit, while Ye Jiao Teng (Shou Wu Teng) nourishes Heart Blood and calms the spirit through the Heart channel. Together they address both the emotional root (constraint) and the physical basis (Blood nourishment) of insomnia, creating a more complete calming effect than either herb alone.

When to use: Insomnia and restless sleep caused by emotional distress, worry, or depression, especially when accompanied by dream-disturbed sleep.

Bai Shao
Bai Shao 1:1 (He Huan Pi 10-15g : Bai Shao 10-15g)

He Huan Pi opens and resolves Liver constraint while Bai Shao nourishes Liver Blood and softens the Liver. The combination addresses Blood-deficient Liver constraint: He Huan Pi unblocks the stagnation while Bai Shao replenishes the Blood that allows the Liver to function smoothly. Together they calm the spirit, ease irritability, and soothe emotional tension.

When to use: Depression, irritability, and insomnia with underlying Blood deficiency, such as pale complexion, dry eyes, or menstrual irregularity.

Yu Jin
Yu Jin 1:1 (He Huan Pi 10-15g : Yu Jin 10g)

Both herbs resolve constraint, but through different mechanisms: He Huan Pi gently lifts the spirit and calms the Heart, while Yu Jin powerfully moves Qi and Blood stagnation and opens the orifices. Together they create a strong Qi-and-spirit-freeing combination that addresses both the emotional and the physical aspects of depression and frustration.

When to use: Stubborn depression, emotional stagnation, or chest oppression where the emotional constraint has been present for a long time and simple spirit-calming herbs are insufficient.

Bai Zi Ren
Bai Zi Ren 1:1 (He Huan Pi 10-15g : Bai Zi Ren 10-15g)

He Huan Pi resolves emotional constraint and lifts mood, while Bai Zi Ren nourishes Heart Blood and calms the spirit with its oily, enriching nature. The pair addresses insomnia from both the stagnation side (He Huan Pi) and the deficiency side (Bai Zi Ren), making it effective for patients whose poor sleep involves both emotional distress and depletion.

When to use: Insomnia with anxiety and palpitations in patients who are both emotionally constrained and constitutionally depleted, such as after prolonged illness or in the elderly.

Comparable Ingredients

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

Suan Zao Ren
He Huan Pi vs Suan Zao Ren

Both calm the spirit and treat insomnia, but Suan Zao Ren works primarily by nourishing Heart and Liver Blood and Yin, making it better for insomnia due to Blood or Yin deficiency (night sweats, palpitations, dry mouth). He Huan Pi works by resolving emotional constraint and Liver Qi stagnation, making it better for insomnia rooted in depression, frustration, or grief. Suan Zao Ren nourishes; He Huan Pi unblocks.

He Huan Hua
He Huan Pi vs He Huan Hua

He Huan Hua (silk tree flower) comes from the same plant and shares similar spirit-calming and depression-relieving actions, but is lighter and more aromatic, better suited for mild emotional distress and Qi-level constraint. He Huan Pi (the bark) enters the Blood level more deeply and has additional actions of invigorating Blood, reducing swelling, and healing injuries that the flower does not share. For purely emotional symptoms, either can be used; for trauma or abscesses, the bark is required.

Yuan Zhi
He Huan Pi vs Yuan Zhi

Both calm the spirit and are used for insomnia and emotional disturbance. Yuan Zhi is warm, bitter, and acrid, and its primary mechanism is to expel Phlegm obstructing the Heart orifices and to promote Heart-Kidney communication. He Huan Pi is neutral and sweet, working by resolving Liver constraint and gently harmonising the spirit. Yuan Zhi is better when Phlegm or poor memory with mental dullness is prominent; He Huan Pi is better when emotional constraint and mood disturbance are central.

Common Substitutes & Adulterants

Related species and common adulterations to be aware of when sourcing He Huan Pi

The most common adulterant is the bark of Shan He Huan (山合欢, Albizia kalkora), a closely related species in the same genus. Shan He Huan bark is visually similar but can be distinguished by its thicker bark, rougher and more deeply fissured outer surface on older specimens, less prominent or absent lenticels on mature bark, and a bland taste without the characteristic tongue-prickling sensation. Shan He Huan does not possess the same therapeutic effects as true He Huan Pi and should not be used as a substitute. He Huan Pi has also been reported as a fraudulent substitute for Hou Po (厚朴, Magnolia bark) in some markets. When cut into prepared medicine slices (饮片), the two barks can appear similar in shape and colour. They are distinguished by Hou Po's distinctly bitter, pungent taste (with a numbing sensation from magnolol), its oily cross-section, and much thicker bark. The two have completely different therapeutic actions. Additionally, He Huan Pi may be confused with Qin Pi (秦皮, Fraxinus bark) or Hai Tong Pi (海桐皮, Erythrina bark) due to superficial similarities. Qin Pi has grey-white dot-like lenticels and a bitter taste; Hai Tong Pi has distinctive conical thorn-like protrusions on its surface.

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

Toxicity Classification

Classical Chinese pharmacopoeia toxicity rating for He Huan Pi

Non-toxic

He Huan Pi is classified as non-toxic in the Chinese Pharmacopoeia. Clinical experience has shown it is well tolerated even at high doses; reports describe use up to 60g and even 90g in decoction without adverse effects. The primary active constituents are triterpenoid saponins, which are responsible for both the therapeutic effects and the mild tongue-tingling and throat discomfort noticed when tasting the raw herb. The saponins can cause mild haemolysis in vitro (a property common to many saponin-containing herbs) but this is not clinically significant at standard oral doses. The saponins do have notable anti-fertility activity in animal studies (anti-implantation and uterine stimulation effects), which is the basis for the pregnancy contraindication rather than any toxic effect per se. At therapeutic doses in decoction, the herb is considered safe for most adults.

Contraindications

Situations where He Huan Pi should not be used or requires extra caution

Avoid

Pregnancy: He Huan Pi contains saponins that have demonstrated significant anti-fertility and uterine-stimulating effects in pharmacological studies, with actions similar to oxytocin. It should not be used during pregnancy.

Avoid

Wind-Heat patterns with spontaneous sweating (风热自汗): classical texts prohibit use in this condition, as the herb's properties are unsuited for exterior Heat conditions.

Avoid

Insomnia caused by external pathogenic factors (外感不眠), such as during colds or influenza: the herb addresses internal emotional causes of insomnia, not those from acute infections.

Caution

Gastritis or active stomach inflammation: the herb contains saponins and tannins that may irritate the gastric lining. Use with caution or avoid in patients with significant gastrointestinal sensitivity.

Caution

Concurrent use of sedative medications or CNS depressants: He Huan Pi may potentiate drowsiness and excessive sedation. Use with caution and monitor closely.

Caution

Pre-surgical patients: due to potential central nervous system effects, discontinue at least two weeks before scheduled surgery to avoid interaction with anesthesia.

Special Populations

Important considerations for pregnancy, breastfeeding, and pediatric use

Pregnancy

Contraindicated during pregnancy. Pharmacological studies have demonstrated that He Huan Pi contains saponins with significant anti-fertility and uterine-stimulating effects. In animal studies, the bark's cold water extract and total saponins caused uterine contractions similar to oxytocin, anti-implantation effects (pregnancy termination rate up to 86% in rats), and fetal resorption when administered into the amniotic cavity. The saponins showed no estrogenic activity, indicating the mechanism involves direct uterine stimulation rather than hormonal disruption. These findings support the traditional caution against use during pregnancy.

Breastfeeding

Insufficient safety data is available for use during breastfeeding. While the herb is generally considered mild and non-toxic, the saponin constituents responsible for its anti-fertility and uterine-stimulating effects raise theoretical concerns about transfer through breast milk. The sedative properties could also potentially affect a nursing infant. Until more safety data is available, it is advisable to avoid use or consult a qualified practitioner before using He Huan Pi while breastfeeding.

Children

He Huan Pi is considered a mild, gentle herb with a neutral temperature, which makes it more suitable for children than many other sedative herbs. It may be used for older children experiencing emotional disturbance, anxiety, or insomnia at reduced dosages (typically one-third to one-half of the adult dose, depending on age and body weight). It is not commonly used in very young children or infants without practitioner guidance. As with all herbs in children, shorter treatment courses and careful observation are advisable.

Drug Interactions

If you are taking pharmaceutical medications, be aware of these potential interactions with He Huan Pi

Sedative medications (benzodiazepines, barbiturates, sleep aids): He Huan Pi has demonstrated sedative and hypnotic activity in pharmacological studies. It may potentiate the effects of sedative drugs, increasing drowsiness and CNS depression. Concurrent use should be monitored carefully.

Antidepressant medications (SSRIs, SNRIs, MAOIs): Research has shown that compounds in He Huan Pi can inhibit the serotonin transporter (SERT) and modulate 5-HT1A receptor activity. Concurrent use with serotonergic antidepressants could theoretically increase serotonin levels excessively. Caution is warranted, particularly with SSRIs.

Anaesthetic agents: Due to its central nervous system effects, He Huan Pi may enhance the effects of anaesthesia. It is advisable to discontinue use at least two weeks before scheduled surgery.

Anticoagulant and antiplatelet medications: He Huan Pi has traditional Blood-activating (活血) properties. While no specific interactions with warfarin or similar drugs have been documented in clinical studies, theoretical additive effects on bleeding risk should be considered.

Dietary Advice

Foods and dietary considerations when taking He Huan Pi

No strong dietary restrictions are associated with He Huan Pi. Since the herb is used primarily for emotional conditions and insomnia, general supportive dietary advice applies: favour calming, easily digestible foods and avoid excessive stimulants such as strong tea, coffee, and alcohol in the evening when using the herb for sleep support. When using it for its Blood-activating properties in trauma recovery, warm, nourishing foods that support Blood production (such as soups with dark leafy greens, dates, and bone broth) are beneficial. Avoid excessively cold or raw foods if digestive sensitivity is a concern, as the saponin content can mildly irritate the stomach.

Botanical Description

Physical characteristics and morphology of the He Huan Pi source plant

Albizia julibrissin Durazz. is a deciduous tree in the legume family (Fabaceae), typically growing 6 to 10 metres tall, occasionally reaching higher. The trunk has greyish-black bark, and the young branches are smooth with angular ridges. The leaves are bipinnate (doubly compound), arranged alternately, with 5 to 15 pairs of pinnae, each bearing 11 to 30 pairs of tiny, sickle-shaped leaflets. A distinctive feature is that the leaflets fold together at dusk and reopen at dawn, a behaviour called "sleep movement" (nyctinasty), which gives the tree its Chinese name meaning "collective happiness" or its folk name "night-closing tree."

The flowers appear in summer (June to August), forming fluffy, globe-shaped heads at the branch tips. Each flower has a funnel-shaped corolla with numerous long, silky stamens that are pink at the tips, giving the tree its Western common name "silk tree" or "mimosa." The fruit is a flat, papery pod 8 to 15 centimetres long that matures from August to October, turning yellowish-brown. The tree grows naturally on mountain slopes and along roadsides, and is widely cultivated in gardens throughout China and East Asia. It is tolerant of drought and various soil types.

Sourcing & Harvesting

Where He Huan Pi is sourced, when it's harvested or collected, and how to assess quality

Harvesting season

Summer to autumn (June through October), when the bark is stripped from the trunk, sun-dried, and cut into segments.

Primary growing regions

He Huan Pi is distributed throughout most of China, from the northeast to the south and southwest. The primary commercial producing regions are Hubei (the largest producer), Jiangsu, Zhejiang, Anhui, Sichuan, and Henan provinces. The Yangtze River valley and Yellow River basin regions are considered core production areas. While there is no single famous dao di (terroir) designation for this herb comparable to some other herbs, Hubei province is traditionally associated with the highest output and consistent quality. The tree grows both wild and cultivated on mountain slopes, roadsides, and in gardens.

Quality indicators

Good quality He Huan Pi bark is thin and uniform, appearing as rolled cylindrical or half-cylindrical pieces. The outer surface should be greyish-brown to greyish-green, without deep cracks or roughness, and should have clearly visible, prominent elliptical lenticels (皮孔) that are reddish-brown in colour. The inner surface should be pale yellowish-brown or yellowish-white, smooth, with fine longitudinal striations. The bark should be hard but brittle, snapping cleanly with a fibrous, pale yellowish fracture surface. Good material has a faintly fragrant aroma and a mild, slightly astringent taste that lightly prickles the tongue, followed by a subtle uncomfortable sensation in the throat (this indicates adequate saponin content). Thinner, younger bark with clearly visible lenticels is preferred over thick, rough old bark.

Classical Texts

Key passages from the classical Chinese medical texts that describe He Huan Pi and its therapeutic uses

Shen Nong Ben Cao Jing (《神农本草经》)

Original: 主安五脏，和心志，令人欢乐无忧。

Translation: "It governs the calming of the five Zang organs, harmonizes the Heart and the will, and makes one joyful and free of worry."

Ben Cao Gang Mu (《本草纲目》, Li Shizhen)

Original: 和血，消肿，止痛。

Translation: "Harmonizes Blood, reduces swelling, and stops pain."

Ben Cao Hui Yan (《本草汇言》)

Original: 合欢皮，甘温平补，有开达五神，消除五志之妙应也。……味甘气平，主和缓心气，心气和缓，则神明自畅而欢乐无忧。如俗语云，萱草忘忧，合欢蠲忿，正二药之谓欤。

Translation: "He Huan Pi, sweet and mild in nature, has the wondrous effect of opening and reaching the five spirits and dispelling the five emotions. Its sweet flavour and neutral Qi principally ease and moderate the Heart Qi. When Heart Qi is eased, the spirit (Shen) flows freely, bringing joy without worry. As the folk saying goes: 'Daylily [Xuan Cao] dispels sorrow, Albizia [He Huan] eliminates resentment' — this is precisely the meaning of these two herbs."

Ben Cao Qiu Zhen (《本草求真》)

Original: 合欢，气缓力微，用之非止钱许可以奏效，故必重用久服，方有补益怡悦心志之效矣。

Translation: "He Huan has a gentle nature and mild strength. Using just a small amount will not produce results. Therefore, it must be used in substantial doses and taken over time before it yields effects of nourishing, delighting, and calming the mind."

Qian Jin Fang (《千金方》, Sun Simiao) — Huang Hun Tang

Original: 咳有微热，烦满，胸心甲错，是为肺痈。黄昏（是合昏皮也）手掌大一片。细切，以水三升，煮取一升，分三服。

Translation: "Cough with mild fever, irritability and fullness, scaly skin on the chest — this is lung abscess. Take one palm-sized piece of Huang Hun (which is He Huan bark), cut finely, decoct in three sheng of water down to one sheng, divide into three doses."

Historical Context

The history and evolution of He Huan Pi's use in Chinese medicine over the centuries

He Huan Pi has one of the longest continuous histories of use among spirit-calming herbs in Chinese medicine. It was first recorded in the Shen Nong Ben Cao Jing (Divine Farmer's Classic of Materia Medica), dating to the Han Dynasty, where it was classified as a middle-grade herb. The classical entry describes it simply as calming the five organs and making one "joyful and free of worry." This early emphasis on its emotional and psychological benefits has remained the herb's defining identity for two thousand years.

The Chinese name "He Huan" (合欢, meaning "collective happiness" or "union of joy") and one of its folk names "Ye He" (夜合, "night-closing") both refer to the tree's remarkable behaviour: its delicate leaflets fold together at nightfall and reopen at dawn, as if the tree itself is settling into peaceful sleep. This observation led classical physicians to associate the bark with the ability to help people find restful closure at the end of the day. A famous classical aphorism pairs it with the daylily: "Xuan Cao forgets sorrow, He Huan eliminates resentment" (萱草忘忧，合欢蠲忿). During the Tang Dynasty, Sun Simiao's Qian Jin Fang expanded its uses beyond emotional conditions to include treatment of lung abscess (肺痈). Zhu Danxi (朱丹溪) of the Jin-Yuan medical era noted the value of combining He Huan Pi with white wax in topical plaster preparations, and the Ben Cao Yan Yi Bu Yi praised its ability to "supplement Yin with rapid effect, grow flesh, and join sinew and bone." The herb's gentle, neutral nature and broad applicability have made it a staple in formulas for emotional disturbance, insomnia, and trauma recovery throughout Chinese medical history.

Modern Research

5 published studies investigating the pharmacological effects or clinical outcomes of He Huan Pi

1

Anxiolytic-like effects of extracts from Albizzia julibrissin bark in the elevated plus-maze in rats (Preclinical study, 2004)

Kim WK, Jung JW, Ahn NY, Oh HR, Lee BK, Oh JK, Cheong JH, Chun HS, Ryu JH. Life Sciences. 2004; 75(23): 2787-2795.

This animal study tested the water extract of Albizia julibrissin bark in rats using the elevated plus-maze, a standard anxiety test. At doses of 100 or 200 mg/kg given orally (single or repeated for 7 days), the extract significantly increased time spent in open arms compared to controls, indicating reduced anxiety. Importantly, this effect occurred without changes in locomotor activity or muscle relaxation, suggesting a specific anxiolytic action rather than general sedation.

Link
2

Antidepressant-like effects of Albizzia julibrissin in mice: Involvement of the 5-HT1A receptor system (Preclinical study, 2007)

Kim JH, Kim SY, Lee SY, Jang CG. Pharmacology, Biochemistry and Behavior. 2007; 87(1): 41-47.

Researchers tested a methylene chloride fraction of A. julibrissin bark in mice using the tail suspension test. At 200 mg/kg orally, it significantly reduced immobility time (a marker of antidepressant effect) comparable to the conventional antidepressant imipramine. The effect was blocked by a 5-HT1A receptor antagonist, suggesting the antidepressant action works through the serotonin 5-HT1A receptor system.

PubMed
3

Two lignan glycosides from Albizia julibrissin Durazz. noncompetitively inhibit serotonin transporter (Preclinical study, 2022)

Huang B, Wu Y, Li C, Tang Q, Zhang YW. Molecules. 2022; 27(6): 1869.

This study isolated two lignan glycosides from Albizia julibrissin bark and found they inhibit the serotonin transporter (SERT) through a novel noncompetitive mechanism, different from conventional antidepressant drugs like SSRIs. The compounds induced a conformational change in SERT, reducing serotonin reuptake. This provides a molecular-level explanation for the traditional antidepressant use of the herb.

PubMed
4

Molecular basis and mechanism of action of Albizia julibrissin in depression treatment and clinical application of its formulae (Review, 2023)

Huang B, Wu Y, Li C, Tang Q, Zhang YW. Chinese Herbal Medicines. 2023; 15(2): 201-213.

A comprehensive review summarizing the antidepressant mechanisms of A. julibrissin. The authors found that the herb produces antidepressant effects through multiple pathways, including modulating monoaminergic neurotransmission, the HPA (stress hormone) axis, BDNF signalling, and the neuroimmune system. The review also covered clinical applications of He Huan-containing formulas used alongside conventional antidepressants in practice.

PubMed
5

Albizia julibrissin ameliorates memory loss induced by insomnia in Drosophila (Preclinical study, 2019)

Chang CW, Chen MJ, Chiang HM, et al. Evidence-Based Complementary and Alternative Medicine. 2019; 2019: 7395962.

Using a Drosophila (fruit fly) model of sleep deprivation, researchers found that A. julibrissin water extract ameliorated the memory loss caused by short-term insomnia. The extract protected 3-hour memory function without affecting immediate learning. This study is notable as it was conducted at an institution in Taiwan, where A. julibrissin is reported to be the most-prescribed herbal medicine for insomnia.

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.