Herb Fruit (果 guǒ / 果实 guǒ shí)

Zhu Ya Zao

Chinese Honeylocust Fruit · 猪牙皂

Gleditsia sinensis Lam. · Gleditsiae Fructus Abnormalis

Zhu Ya Zao (Chinese Honeylocust Fruit) plant

Images shown are for educational purposes only

Zhu Ya Zao is a powerful phlegm-clearing herb used in Chinese medicine for emergencies involving thick phlegm that blocks the airways or causes loss of consciousness, such as during stroke or severe asthma. It is also applied externally for swellings, abscesses, and skin infections. Because of its strong and potentially harsh effects, it is used in very small doses and is not suitable for those who are pregnant, physically weak, or prone to bleeding.

Category Warm herbs that transform Phlegm-Cold (温化寒痰药)
Therapeutic focus Respiratory Health Emergency Phlegm Relief Skin Health Digestive Regularity

TCM Properties

Temperature

Warm

Taste

Acrid / Pungent (辛 xīn), Salty (咸 xián)

Channels entered

Lungs, Large Intestine

Parts used

Fruit (果 guǒ / 果实 guǒ shí)

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 Zhu Ya Zao does in the body, explained in both everyday and TCM terms

Therapeutic focus

In practical terms, Zhu Ya Zao is primarily used to support these areas of health:

Respiratory Health Emergency Phlegm Relief Skin Health Digestive Regularity

TCM Actions

In TCM terminology, these are the specific therapeutic actions that Zhu Ya Zao performs to restore balance in the body:

Expels Phlegm and Opens the Orifices Disperses Swelling and Dissipates Nodules Opens the Orifices and Revives Consciousness Disperses Wind Expels Parasites

How these actions work

'Expels phlegm and opens the orifices' is the primary action of this herb. It has an extremely powerful ability to dislodge thick, stubborn phlegm (called 'turbid phlegm' in TCM) that blocks the airways and the sensory orifices. When blown into the nose as a powder, it triggers vigorous sneezing that can rouse someone from unconsciousness. When taken internally, it can induce vomiting of copious sticky phlegm. This action is used in emergencies such as stroke with locked jaw and loss of consciousness, or epileptic seizures where thick phlegm obstructs the throat and airways.

'Dissipates clumps and reduces swelling' refers to the herb's ability to break up firm accumulations and reduce swellings when applied externally. It is used as a paste or powder for abscesses, boils, and other swollen lesions that have not yet ruptured. Its acrid, warm, and penetrating nature helps disperse stagnation and draw toxins to the surface.

'Opens blockages and frees the passages' describes how this herb's sharp, penetrating quality can unblock obstructions throughout the body. This includes relieving severe constipation caused by dry stool accumulation and clearing blocked nasal passages. The Ben Cao Gang Mu describes it as being able to "open all the upper and lower orifices" when blown or guided into the body.

'Dispels Wind' relates to its traditional use for conditions attributed to Wind pathogen, such as Wind-type skin lesions (scabies, ringworm), headaches caused by Wind, and the sudden onset of stroke-like symptoms (which TCM classically attributes to Wind-Phlegm). 'Kills parasites' refers to its topical use against skin parasites and fungal infections.

Patterns Addressed

In TCM, symptoms cluster into recognizable patterns of disharmony. Zhu Ya Zao is used to help correct these specific patterns.

Why Zhu Ya Zao addresses this pattern

Zhu Ya Zao is warm and acrid with a strong penetrating quality that directly targets the Lung channel. In Wind-Phlegm blocking the orifices, thick phlegm driven by internal Wind obstructs the sensory passages and blocks consciousness. The herb's acrid taste disperses and opens, while its salty taste softens hardened phlegm masses. Its warm nature activates Qi movement to break through the phlegm obstruction. This makes it a critical emergency herb for sudden loss of consciousness with phlegm gurgling in the throat, locked jaw, and inability to speak. It is classically paired with Ming Fan (alum) in formulas like Xi Xian San to induce vomiting of the obstructing phlegm and restore consciousness.

A practitioner would look for one or more of these signs

Loss Of Consciousness

Sudden loss of consciousness with phlegm rattling in the throat

Lockjaw

Jaw clenched shut, unable to open the mouth

Aphasia

Inability to speak due to phlegm obstruction

Seizures

Epileptic seizures with copious phlegm

Commonly Used For

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

Arises from: Phlegm

TCM Interpretation

In TCM, stroke (called Zhong Feng, meaning 'struck by Wind') is understood through two broad categories: 'channel stroke' affecting the limbs and face, and 'organ stroke' where the deeper organs are affected, producing unconsciousness, locked jaw, and inability to speak. The organ-level stroke involves internal Wind stirring up thick Phlegm that surges upward and blocks the clear orifices of the Heart and Brain. The throat fills with phlegm, the jaw locks shut, and the person loses consciousness. The critical distinction TCM makes is between a 'closed' pattern (where everything is blocked and the fists are clenched) and a 'collapsed' pattern (where everything is open and limp). Zhu Ya Zao is only appropriate for the closed pattern with excess phlegm.

Why Zhu Ya Zao Helps

Zhu Ya Zao's primary strength in stroke emergencies is its unmatched ability to dislodge obstructing phlegm from the throat and sensory orifices. Its acrid, warm, and intensely penetrating nature cuts through the thick, sticky phlegm that has blocked consciousness. When blown into the nose as a powder, it triggers powerful sneezing that can physically break through the phlegm obstruction and rouse the patient. When combined with Ming Fan (alum) in the classical formula Xi Xian San, it induces vomiting of the phlegm, clearing the throat and restoring the ability to breathe and swallow. This is strictly an emergency intervention for the acute closed-type stroke, not a long-term treatment.

Also commonly used for

Seizures

Epilepsy with copious phlegm

Chronic Bronchitis

Chronic cough with abundant viscous sputum

COPD

Acute exacerbation with phlegm obstruction

Tonsillitis

Acute throat swelling and obstruction

Constipation

Severe constipation with dry, bound stool

Boils

External application for unruptured abscesses and boils

Scabies

Topical use for parasitic skin conditions

Herb Properties

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

Temperature

Warm

Taste

Acrid / Pungent (辛 xīn), Salty (咸 xián)

Channels Entered

Lungs Large Intestine

Parts Used

Fruit (果 guǒ / 果实 guǒ shí)

Dosage & Preparation

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

Standard dosage

1–1.5g

Maximum dosage

Do not exceed 1.5g internally. In decoction, a maximum of 0.3–0.6g is advised due to severe gastrointestinal irritation. As powder for swallowing, do not exceed 0.15g per dose.

Dosage notes

Zhu Ya Zao is most commonly used in pill or powder form rather than in decoction, because the saponins are extremely irritating to the gastrointestinal tract in liquid form. For internal use as pills or powder: 1 to 1.5g. For decoction (used rarely): no more than 0.3 to 0.6g. As fine powder to be swallowed directly: no more than 0.15g per dose. For external use: an appropriate amount of powder can be blown into the nose to induce sneezing, which is the traditional method for opening the orifices in emergency situations such as loss of consciousness. Alternatively, the powder can be mixed with vinegar and applied topically to swellings. Smoke fumigation of the anus using the burning herb has been reported for treating constipation and abdominal distension.

Preparation

Zhu Ya Zao is most commonly processed into pills or fine powder rather than used in standard decoctions, because the saponins are very irritating in liquid form. When used in decoction on rare occasions, only a very small amount (0.3–0.6g) should be added. For nasal insufflation, the herb must be ground into an extremely fine powder. For topical use, mix the powder with vinegar to form a paste. Classical processing methods include roasting with lard (猪脂涂炙) until yellow, or honey-roasting (蜜炙), both of which moderate the herb's harsh properties.

Processing Methods

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

Processing method

Clean sand is heated in a wok over medium heat, then the raw Zhu Ya Zao is added and stir-fried until it puffs up and turns deep brown. The sand is sieved out and the herb is cooled. Alternatively, it can be dry-fried without sand until the surface darkens and becomes glossy.

How it changes properties

Stir-frying moderates the herb's harsh, drastic nature. The raw form has a very strong, irritating effect on the mucous membranes and gastrointestinal tract. After frying, the penetrating orifice-opening power is somewhat reduced, but the phlegm-expelling action remains strong. The processed form is less likely to cause nausea and vomiting.

When to use this form

Use the fried form for chronic phlegm conditions such as stubborn cough with thick sputum and constipation with stool accumulation, where the goal is phlegm expulsion rather than emergency orifice-opening. The raw form is preferred for acute emergencies requiring orifice-opening (nasal insufflation to induce sneezing, or phlegm-purging through vomiting).

Common Herb Pairs

These ingredients are traditionally combined with Zhu Ya Zao for enhanced therapeutic effect

Ming Fan
Ming Fan Zhu Ya Zao 4 pieces : Ming Fan 30g (approximately 1:1 by weight)

Zhu Ya Zao powerfully dislodges and expels thick phlegm while Ming Fan (alum) has an astringent quality that helps draw out and dissolve phlegm accumulations. Together they create a potent phlegm-purging combination that can induce vomiting of copious sticky phlegm to clear blocked orifices and restore consciousness. This is the classical pair in Xi Xian San (Thin Out Drool Powder).

When to use: Emergency treatment of stroke with sudden loss of consciousness, locked jaw, phlegm gurgling in the throat, and inability to speak. Only for excess-type closed patterns, never for deficiency-type collapse.

Ban Xia
Ban Xia 1:1

Both herbs are warm and enter the Lung channel with strong phlegm-resolving actions. Ban Xia dries Dampness and transforms phlegm, while Zhu Ya Zao forcefully dislodges stubborn, sticky phlegm that Ban Xia alone cannot shift. Together they warm the Lungs and powerfully dissolve tenacious phlegm from the chest.

When to use: Chest congestion with thick, sticky phlegm that is extremely difficult to expectorate, persistent cough with turbid sputum. Used in the formula Qian Min Tang (Thousand Gold Pieces Decoction).

Xi Xin
Xi Xin 1:1

Xi Xin (Asarum) is aromatic and strongly penetrating, opening the nasal passages and dispersing Wind-Cold. Zhu Ya Zao adds powerful phlegm-expelling action. Together they combine Wind-dispersing and phlegm-dislodging effects to powerfully open blocked orifices, making them a potent pair for restoring consciousness.

When to use: Stroke with unconsciousness, locked jaw, and phlegm surging upward. Also used for acute convulsions in children with phlegm obstruction. Commonly used as a nasal insufflation powder (blown into the nose to induce sneezing).

Key Formulas

These well-known formulas feature Zhu Ya Zao in a prominent role

Tong Guan San 通关散 King

Tong Guan San (Open the Gate Powder) combines Zhu Ya Zao with Xi Xin and sometimes Bing Pian as a nasal insufflation powder. It is blown into the nostrils to trigger sneezing and rouse patients from unconsciousness due to phlegm obstruction. This showcases the herb's unique ability to open blocked orifices through direct mucous membrane stimulation.

Comparable Ingredients

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

Da Zao
Zhu Ya Zao vs Da Zao

Da Zao Jiao (the full-sized mature fruit of the same Gleditsia sinensis tree) and Zhu Ya Zao (the smaller, abnormal fruit from the same tree) share nearly identical properties and actions. Classical sources traditionally regard Zhu Ya Zao as superior in quality for dispelling Wind-Phlegm, while Da Zao Jiao is considered stronger for resolving Damp-Phlegm. In modern practice, Zhu Ya Zao is the more commonly used form.

Bai Jie Zi
Zhu Ya Zao vs Bai Jie Zi

Both are warm, acrid herbs that resolve stubborn phlegm. Bai Jie Zi (white mustard seed) warms the Lungs and disperses Cold-Phlegm that has settled in the channels and flanks, and is much milder and safer for regular use. Zhu Ya Zao is far more drastic and penetrating, able to force open blocked orifices and induce vomiting of phlegm. Zhu Ya Zao is reserved for acute emergencies and severe phlegm obstruction, while Bai Jie Zi is appropriate for chronic Phlegm-Cold conditions.

Tian Nan Xing
Zhu Ya Zao vs Tian Nan Xing

Both address Wind-Phlegm patterns including stroke and epilepsy. Tian Nan Xing (Arisaema) dries Dampness, expels Phlegm, and disperses Wind from the channels, making it suitable for inclusion in longer-term formulas for stroke recovery and epilepsy. Zhu Ya Zao is more of an emergency rescue herb with its orifice-opening and phlegm-purging (including emetic) action, used primarily in acute closed-type emergencies rather than ongoing treatment.

Common Substitutes & Adulterants

Related species and common adulterations to be aware of when sourcing Zhu Ya Zao

Zhu Ya Zao is sometimes confused with or substituted by Da Zao Jiao (大皂荚, the normal mature fruit of the same Gleditsia sinensis tree). Da Zao Jiao pods are significantly larger, flatter, and longer (up to 20-30 cm), and contain well-developed seeds. While they share similar properties, Zhu Ya Zao (the seedless abnormal fruit) is traditionally considered the superior medicinal product. The two can be distinguished by size, shape, and the absence of seeds in genuine Zhu Ya Zao. Occasionally, the pods of related Gleditsia species (such as G. japonica or G. australis) may be substituted; these have a different chemical profile and should be rejected. Pods that are worm-eaten, hollow, or lack the characteristic waxy bloom are of inferior quality.

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

Toxicity Classification

Classical Chinese pharmacopoeia toxicity rating for Zhu Ya Zao

Slightly toxic

Zhu Ya Zao contains triterpenoid saponins (gleditsia saponins) as its primary active and potentially toxic components. These saponins are irritant to mucous membranes and can cause haemolysis (destruction of red blood cells) at high concentrations. Symptoms of overdose include severe nausea, intense vomiting, abdominal pain, and profuse diarrhea. The powdered herb is highly irritating to the nasal mucosa and respiratory tract, and inhaling the dust readily induces sneezing. When used within the recommended very small dosage range (1 to 1.5g in pills or powder, or no more than 0.3 to 0.6g in decoction), toxicity is avoided. The classical formula Xi Xian San (稀涎散) warns explicitly not to induce excessive vomiting, as overuse 'may endanger life.'

Contraindications

Situations where Zhu Ya Zao should not be used or requires extra caution

Avoid

Pregnancy. Zhu Ya Zao has strong dispersing properties and has been historically documented as capable of inducing miscarriage (《药性论》 states it can 'cause fetal loss'). Strictly prohibited during pregnancy.

Avoid

Active hemoptysis (coughing blood) or hematemesis (vomiting blood). The herb's powerful, upward-driving action to expel phlegm can worsen active bleeding in the lungs or stomach.

Avoid

Qi deficiency or Yin deficiency without substantial phlegm obstruction. This herb is extremely sharp and dispersing in nature. Using it in weakened or depleted patients can exhaust body fluids and worsen the condition. The 《本草经疏》 specifically warns against using it for stroke-like conditions caused by Yin deficiency with internal fire.

Caution

Bleeding tendency or coagulation disorders. The strong, penetrating nature of the herb may aggravate bleeding conditions.

Caution

Excessive internal dosage. When used in decoction internally, the herb is extremely irritating to the gastrointestinal tract. Overdose can cause intense vomiting and diarrhea. Internal decoction dosage must be kept very small.

Classical Incompatibilities

Traditional Chinese pharmacological incompatibilities — herbs or substances to avoid combining with Zhu Ya Zao

Zhu Ya Zao does not appear on the Eighteen Incompatibilities (十八反) or Nineteen Mutual Fears (十九畏) lists. However, the 《本草经集注》 records traditional cautions: it is 'averse to' (恶) Mai Men Dong (Ophiopogon), and 'fears' (畏) Kong Qing (azurite), Ren Shen (Ginseng), and Ku Shen (Sophora flavescens). These are not part of the standard incompatibility lists but represent classical cautions that some practitioners observe.

Special Populations

Important considerations for pregnancy, breastfeeding, and pediatric use

Pregnancy

Contraindicated during pregnancy. The 《药性论》 explicitly states that Zhu Ya Zao can cause miscarriage (能堕胎). Its strongly dispersing, penetrating nature and ability to forcefully move Qi and expel phlegm pose a serious risk of stimulating uterine contractions and disrupting the pregnancy. This herb must not be used at any stage of pregnancy.

Breastfeeding

Not recommended during breastfeeding. The saponin compounds in Zhu Ya Zao may transfer into breast milk, and their irritant properties could adversely affect the nursing infant's digestive system. No safety data exists for use during lactation. Should be avoided unless specifically prescribed by a qualified practitioner who has weighed the risks.

Children

Zhu Ya Zao should be used with great caution in children and only under close professional supervision. The herb's strong, irritating nature and slight toxicity make it poorly suited for the immature digestive systems of young children. Dosage must be significantly reduced compared to adult doses (typically to one-third or less). External use (such as blowing powder into the nose to induce sneezing in emergency situations like loss of consciousness) may be more appropriate than internal administration in paediatric cases. Avoid use in infants.

Drug Interactions

If you are taking pharmaceutical medications, be aware of these potential interactions with Zhu Ya Zao

No well-documented pharmaceutical drug interactions have been established through clinical studies. However, based on the known pharmacological properties of Gleditsia saponins, the following theoretical concerns should be considered:

  • Anticoagulant and antiplatelet drugs: Saponins can cause haemolysis at high concentrations. Use with blood-thinning medications (such as warfarin or heparin) should be approached with caution due to the theoretical risk of compounded effects on blood.
  • Mucosal-irritant medications: Since Zhu Ya Zao is strongly irritating to the gastrointestinal mucosa, concurrent use with NSAIDs or other drugs known to irritate the stomach lining could increase the risk of gastric damage.
  • Sedatives and CNS depressants: When used as a stimulating agent to open orifices (e.g. blown into the nose to induce sneezing for loss of consciousness), its effects may theoretically oppose sedative medications.

Dietary Advice

Foods and dietary considerations when taking Zhu Ya Zao

When taking Zhu Ya Zao internally, avoid cold, raw, and greasy foods, which can generate more phlegm and counteract the herb's phlegm-expelling action. Avoid excessively spicy or irritating foods, as the herb itself is already strongly stimulating to the digestive system. Light, easily digestible meals are recommended to reduce the burden on the stomach and intestines.

Botanical Description

Physical characteristics and morphology of the Zhu Ya Zao source plant

Zhu Ya Zao is not a separate species but rather the dried, sterile (seedless) abnormal fruit produced by the Chinese honey locust tree, Gleditsia sinensis Lam. (family Fabaceae/Leguminosae). The tree is a large deciduous tree that can grow up to 30 metres tall, with pinnately compound leaves resembling those of the pagoda tree (Sophora), and distinctive branching thorns that grow directly from the trunk and branches. It flowers from March to May with yellowish-white racemes.

The abnormal fruits form when a mature honey locust tree is injured or has grown old. In traditional cultivation areas like Sichuan's Qingchuan County, farmers deliberately wound the tree trunks in winter or early spring by cutting into them or driving nails into the bark, a technique called 'releasing sap' (放浆, fàng jiāng). This stimulates the tree to produce the small, curved, seedless pods known as Zhu Ya Zao rather than the normal full-sized pods (Da Zao Jiao). The resulting abnormal fruits are cylindrical, slightly flattened, and curved like a crescent moon, 5 to 11 cm long, resembling a pig's tusk, which is the origin of the name ('pig tooth soap').

Sourcing & Harvesting

Where Zhu Ya Zao is sourced, when it's harvested or collected, and how to assess quality

Harvesting season

Late autumn, when the fruits are mature. The classical text 《名医别录》 specifies the ninth and tenth lunar months. The pods are collected and sun-dried.

Primary growing regions

Sichuan Province (especially Qingchuan County) is the most important and traditional production area, considered the prime dao di (道地) source. Other significant growing regions include Guizhou, Yunnan, Shandong, Hebei, Henan, Shanxi, and Shaanxi provinces. The Gleditsia sinensis tree grows widely across the basins of the Yellow and Yangtze Rivers.

Quality indicators

Good quality Zhu Ya Zao pods are cylindrical, slightly flattened, and gently curved in a crescent shape, 5 to 11 cm long and 0.7 to 1.5 cm wide. The surface should be purplish-brown or purplish-black in colour, covered with a greyish-white waxy bloom that reveals a glossy surface when rubbed off. Small wart-like bumps and fine linear or mesh-like cracks on the surface are normal. The pods should feel hard and brittle, snapping cleanly when broken. The cross-section should be brownish-yellow, with a spongy centre containing pale green or pale brownish-yellow fibrous threads. Crucially, the pods should contain no seeds (or only undeveloped seed remnants), as the presence of developed seeds indicates a normal fruit (Da Zao Jiao) rather than the medicinally preferred Zhu Ya Zao. The taste should be initially sweet, then sharply pungent and numbing on the tongue. The powder is extremely irritating and should provoke sneezing.

Classical Texts

Key passages from the classical Chinese medical texts that describe Zhu Ya Zao and its therapeutic uses

《神农本草经》(Shen Nong Ben Cao Jing)

Original: 主风痹死肌，邪气，风头泪出，利九窍。

Translation: Treats wind impediment with deadened flesh, pathogenic Qi, wind-induced headache with tearing eyes, and opens the nine orifices.

《名医别录》(Ming Yi Bie Lu)

Original: 疗腹胀满，消谷，除咳嗽囊结，妇人胞不落，明目益精。

Translation: Treats abdominal distension and fullness, aids digestion, eliminates cough with phlegm nodules, treats retained placenta in women, brightens the eyes and benefits the essence.

This text also records: 如猪牙者良，九月十月采荚阴干 (Those shaped like pig's teeth are the best quality; harvest the pods in the ninth and tenth months and dry in the shade).

《本草纲目》(Ben Cao Gang Mu) — Li Shizhen

Original: 皂角，味辛而性燥，气浮而散。吹之导之，则通上下诸窍。服之则治风湿痰喘肿满，杀虫。涂之则散肿消毒，搜风治疮。

Translation: Zao Jiao is pungent in flavour and drying in nature, with Qi that floats and disperses. Blown into the nose or applied directionally, it opens all the upper and lower orifices. Taken internally, it treats wind-dampness, phlegm-wheezing, swelling and fullness, and kills parasites. Applied topically, it disperses swelling, resolves toxins, expels wind, and treats sores.

《药品化义》(Yao Pin Hua Yi)

Original: 皂荚，为搜痰快药。凡痰在肠胃间，可下而愈。若蓄于胸膈上，则横入脂膜，胶固稠粘，消之不能行，泻之不能下……以此同海石为丸，横胸浊痰，使渐消化，搜出凝结，大有神功。

Translation: Zao Jiao is a fast-acting medicine for dislodging phlegm. When phlegm is in the intestines and stomach, it can be purged downward for a cure. But when phlegm accumulates above the diaphragm, it infiltrates horizontally into the membranes, becoming thick, sticky, and fixed, it cannot be dissolved or purged downward. Combined with Hai Shi (pumice) into pills, it gradually dissolves the turbid phlegm lodged across the chest, dislodging congealed accumulations with remarkable efficacy.

Historical Context

The history and evolution of Zhu Ya Zao's use in Chinese medicine over the centuries

The medicinal use of the Gleditsia sinensis fruit dates back over two thousand years. The parent substance, Zao Jia (皂荚), first appeared in the Shen Nong Ben Cao Jing, where it was classified as a lower-grade drug. The distinct name Zhu Ya Zao (猪牙皂) first appeared in the Ming Yi Bie Lu compiled by Tao Hongjing during the Liang Dynasty, which noted that the small, curved fruits 'shaped like pig's teeth' were of superior medicinal quality compared to regular pods. The name reflects the physical resemblance of the small, curved pods to a pig's tusk. It has also been called 'Wu Xi' (乌犀, black rhinoceros horn) by Li Shizhen in the Ben Cao Gang Mu, and other aliases include Ya Zao (牙皂), Xiao Zao (小皂), and Mei Zao (眉皂).

A famous historical application was recorded by Pang Anshi in his Shang Han Zong Bing Lun (Song Dynasty, 1090 CE): during an epidemic of acute throat obstruction (white diphtheria) in the Qizhou and Huangzhou areas of Hubei Province that was killing people within half a day, an official named Pan Chang used a preparation called 'Black Dragon Paste' (黑龙膏) made primarily from Zao Jiao to treat and cure many victims. Li Shizhen later recorded this formula in the Ben Cao Gang Mu. The Qing Dynasty text Ben Cao Xin Bian gave high praise, calling it 'an indispensable emergency drug that should always be in the medicine chest.'

An important botanical clarification was made through field investigations by the Sichuan Institute of Chinese Materia Medica: Zhu Ya Zao and Da Zao Jiao (the normal fruit) grow on the same tree. There is no separate 'pig tooth soap tree.' The abnormal fruits are produced when mature trees are injured or aged. Farmers deliberately wound trees to stimulate production of these medicinally preferred pods.

Modern Research

3 published studies investigating the pharmacological effects or clinical outcomes of Zhu Ya Zao

1

Structure-activity relationships of saponins from Gleditsia sinensis in cytotoxicity and induction of apoptosis (In vitro study, 2004)

Zhong L, Li P, Han J, Qu G, Guo D. Planta Medica, 2004, 70(9): 797-802.

Thirteen triterpenoid saponins were isolated from the anomalous fruits (Zhu Ya Zao) of Gleditsia sinensis using bioassay-guided fractionation. These saponins were tested against six tumor cell lines and found to induce apoptosis in HL-60 leukaemia cells. Researchers identified key structural features in the saponin molecules that are required for cytotoxic activity, providing a model for potential drug design.

PubMed
2

In vitro anti-angiogenesis effects and active constituents of the saponin fraction from Gleditsia sinensis (In vitro study, 2014)

Lu D, Xia Y, Tong B, Zhang C, Pan R, Xu H, Yang X, Dai Y. Integrative Cancer Therapies, 2014, 13(5): 446-457.

The saponin fraction from Gleditsia sinensis anomalous fruits (SFGS) significantly inhibited proliferation, migration, and tube formation of human endothelial cells stimulated by growth factors, without direct cytotoxicity to the endothelial cells themselves. The study identified Gleditsiosides B, I, J, O, and Q as likely key active constituents, suggesting anti-angiogenic effects that may partly explain the traditional use against swellings and tumors.

PubMed
3

Gleditsia species: An ethnomedical, phytochemical and pharmacological review (Review, 2016)

Zhang JP, Tian XH, Yang YX, Liu QX, Wang Q, Chen LP, Li HL, Zhang WD. Journal of Ethnopharmacology, 2016, 178: 155-171.

A comprehensive review of the Gleditsia genus covering traditional uses across multiple cultures, chemical composition, and modern pharmacology. Over 60 compounds (mainly triterpenoid saponins, flavonoids, alkaloids, and phenolics) had been identified across Gleditsia species. The review documented diverse biological activities including anti-tumour, anti-inflammatory, anti-allergic, analgesic, anti-HIV, and antibacterial effects, though most evidence was preclinical.

PubMed

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.