Gan Sui
StarEuphorbia kansui T.N. Liou ex T.P. Wang
Traditionally used for
- Cough & breathing
- Bowel health
- Urinary & fluids
Cautions & contraindications
- Pregnancy
- Liver conditions
- Kidney conditions
- Toxic — professional use only
☯ TCM Properties
Drains Water and Expels Phlegm-Fluids; Disperses Swelling and Dissipates Nodules; Breaks Up Accumulations; Promotes Bowel and Urinary Movement
Traditional Chinese Uses
Gan Sui (euphorbia root, kansui root) is an extremely toxic herb classified among the most powerful and harsh purgatives in Chinese medicine. It is reserved for conditions of severe fluid accumulation in body cavities — including pleural effusion, ascites, and severe edema — when gentler methods have been insufficient. It produces violent intestinal purging and fluid expulsion. Due to its extreme toxicity, it requires careful vinegar processing, strict dosing, and close professional supervision. It is contraindicated with licorice root (Gan Cao).
Pharmacological Effects
- Purgative: Oral ethanolic extract (10-50 g/kg crude herb equivalent) purged about 50% of mice; crude herb extract killed 11 of 58 mice whereas processed herb extract caused no deaths; decoction was not purgative.
Source: Zhu YP. Chinese Materia Medica: Chemistry, Pharmacology and Applications. Harwood Academic, 1998, p. 240.
Relationships
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Botanical Description
Euphorbia kansui T.N. Liou ex S.B. Ho (Euphorbiaceae) is a low perennial herb 25-40 cm tall endemic to north-central China, with milky latex throughout, slender erect stems, narrow linear-lanceolate leaves, and the cyathium inflorescence characteristic of the genus. The fusiform to ovoid tuberous roots are harvested in spring before flowering or in autumn, peeled, and sun-dried. In TCM, Gan Sui is bitter in flavor, cold in nature, and toxic, entering the Lung, Kidney, and Large Intestine channels; it is a powerful downward-draining substance that drives out water accumulation in cases of severe edema, pleural fluid, and ascites. Because of pronounced toxicity, the root is nearly always processed with vinegar before clinical use.
Active Constituents
3-O-(2'E,4'Z-decadienoyl)-20-O-acetylingenol
Ingenane-type diterpene esterConcentration: One of the principal toxic markers of the raw root; substantially reduced by stir-frying with vinegar, which converts it to ingenol
The compound that carries much of the acute toxicity. In zebrafish it had an LC50 of 0.412 micrograms per millilitre, against greater than 100 micrograms per millilitre for ingenol, and it caused reduced heart rate, pericardial oedema and impaired gastrointestinal motility through oxidative damage, inflammation and apoptosis, none of which ingenol produced. Ingenane diterpene esters of this family are also strongly irritant to skin and mucous membranes.
Kansuinine A
Macrocyclic jatrophane-type diterpene esterA characteristic multi-oxygenated diterpene of this species and one of the constituents whose content falls during vinegar processing. Its solubility in decoction is reduced when the proportion of licorice in a formula is high, which is one chemical strand of the classical kansui-licorice incompatibility.
Kansuinine B
Macrocyclic jatrophane-type diterpene esterIsolated alongside kansuinine A and part of the same irritant diterpene group. Contents of most of these toxic terpenoids drop by roughly 7 to 95 percent after vinegar processing.
Kansuiphorin A and kansuiphorin B
Ingenane-type diterpene estersTwo diterpene esters isolated from the root and reported as antileukaemic in the original 1991 characterisation. They belong to the same ingenane family as the acutely toxic markers, so the antitumour interest and the toxicity are not separable properties of the drug.
Euphol (da ji er xi chun, euphadienol)
Tetracyclic triterpene alcoholConcentration: The Chinese Pharmacopoeia assay marker for the drug: not less than 0.12 percent, calculated on the dried basis
The compound by which the crude drug is standardised. It is a quality marker rather than the toxic principle, so a Pharmacopoeia-compliant assay does not by itself tell you the diterpene ester load, which is what determines toxicity and what processing is intended to reduce.
⚠ Drug Interactions
Licorice / Gan Cao (Glycyrrhiza uralensis and related species), including licorice-containing confectionery and supplements
In malignant pleural effusion rats given kansui with licorice at ratios from 4:1 to 0.1:1, factor analysis of eight toxicity indices and five efficacy indices showed toxicity rising and efficacy falling as the licorice proportion increased, with the crossover between the 2:1 and 1:1 ratios. The chemistry runs the same way: at higher licorice proportions the solubilising effect on kansuinine A decreases through precipitation or colloidal aggregation. The classical prohibition and the animal data agree, which is unusual and worth taking seriously.
Clinical note: Do not put Gan Sui and Gan Cao in the same formula, and check that the patient is not separately taking licorice tea, throat lozenges or a licorice-containing supplement. Because licorice appears in a very large share of Chinese formulas, review the whole prescription, not just the one you wrote.
Digoxin and other cardiac glycosides
Gan Sui is a drastic cathartic that drives large-volume watery stool and fluid loss, which is the entire point of its use for pleural effusion, ascites and oedema. Potassium loss through the gut lowers the threshold for cardiac glycoside toxicity, an established consequence of any strong purgative. There is no study of this specific combination; the risk is inferred from the drug's mechanism of action, which is not in doubt.
Clinical note: Do not use in patients taking digoxin. If a purgative approach is genuinely necessary, monitor potassium and use a gentler agent.
Loop and thiazide diuretics (e.g. furosemide, hydrochlorothiazide)
Both act to remove fluid, by different routes. In the rat pleural effusion study furosemide was used as the positive control against which kansui was compared, which makes the overlap of intended effect explicit. Combining them stacks two sources of volume and potassium loss in patients who are frequently already fluid-depleted.
Clinical note: Avoid concurrent use. If it happens, check urea, creatinine and electrolytes and watch for postural hypotension.
Orally administered drugs generally, especially those with a narrow therapeutic index or modified-release formulations (e.g. levothyroxine, oral contraceptives, anticonvulsants, warfarin)
Drastic catharsis shortens intestinal residence time, and modified-release preparations in particular may be expelled before release is complete. This is a general property of strong purgatives rather than a finding specific to this species.
Clinical note: Separate oral medication from the herb, and expect that on a day of strong purgation absorption of anything taken by mouth is unreliable. Reconsider entirely for patients on anticoagulants or antiepileptics.
Any use in pregnancy, and any internal use of the unprocessed root
The Chinese Pharmacopoeia classifies the drug as toxic, sets the dose of the vinegar-processed root at 0.5 to 1.5 g given in pills or powders rather than decoction, restricts the raw drug to external use, and contraindicates it in pregnancy. The diterpene esters are strongly irritant to skin and mucous membranes and, at higher doses, damaging to heart, liver and kidney; ingenane diterpene esters are also protein kinase C activators of the tumour-promoter structural family. Vinegar stir-frying is not optional refinement - it converts 3-O-(2'E,4'Z-decadienoyl)-20-O-acetylingenol to the far less toxic ingenol and cuts most toxic terpenoid contents by roughly 7 to 95 percent.
Clinical note: Use only vinegar-processed Gan Sui internally, only in pills or powders, only at 0.5 to 1.5 g, and never in pregnancy, in the frail or debilitated, or in anyone with significant hepatic or renal impairment. Handle the raw drug with gloves; it is a mucous membrane irritant.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| powder | 0.5–1.5 g | — | — | — | ChP 2025. 炮制后多入丸散用 — processed, usually in pills or powder. Contraindicated in pregnancy; NOT combined with Gan Cao (eighteen incompatibilities). Corrected from a generic 6-15g decoction filler value generated from tcm_category. |
| topical | Appropriate amount | — | — | — | ChP 2025. 外用适量，生用 — raw, externally. |
Dui Yao — Herb Pairs
The classical two-herb combinations this herb appears in, each with an action neither herb has alone.
Drastic expulsion of fluid combined with purging of heat, together driving out water and heat bound in the chest and epigastrium.
Major chest binding (da jie xiong) with water and heat. Toxic, drastic purgative; for robust patients only, stop once effect is achieved, contraindicated in pregnancy.
Core pair of a classical formula — Da Xian Xiong Tang, Shang Han Lun (Zhang Zhongjing)
Jujube protects the stomach qi and moderates the harshness of the water-expelling herb, allowing fluid to be expelled with less injury to the middle burner.
Classic protective pairing in Shi Zao Tang, where the powdered expellants are taken with jujube decoction. The protection is partial; Gan Sui remains toxic and contraindicated in pregnancy.
Core pair of a classical formula — Shi Zao Tang, Shang Han Lun (Zhang Zhongjing)
Two harsh water-expelling herbs used together to expel pooled fluids from the chest, hypochondrium and abdomen.
Suspended fluid and severe edema in robust patients. Toxic, drastic purgative; for robust patients only, stop once effect is achieved, contraindicated in pregnancy. Both are incompatible with Gan Cao (eighteen incompatibilities).
Core pair of a classical formula — Shi Zao Tang, Shang Han Lun (Zhang Zhongjing)
Two harsh water-expelling herbs used together to drive out pooled fluid in the chest and hypochondrium.
Suspended fluid (xuan yin) and severe edema in robust patients. Toxic, drastic purgative; for robust patients only, stop once effect is achieved, contraindicated in pregnancy. Both are incompatible with Gan Cao (eighteen incompatibilities).
Core pair of a classical formula — Shi Zao Tang, Shang Han Lun (Zhang Zhongjing)
Evidence Tier
Moderate evidence · 4 studiesRecorded studies by study design, strongest design at the top. This is a study-design tier only, not a GRADE rating: it does not weigh risk of bias, consistency or precision.
Systematic review / meta-analysis
0
Randomized controlled trial
1
0 verified · 1 unverified
Other clinical trial
0
Observational / case report
0
In vitro / animal
3
3 verified · 0 unverified
Show 3 studies
- Toxicity Reduction of Euphorbia kansui Stir-Fried with Vinegar Based on Conversion of 3-O-(2′E,4′Z-Decadi-enoyl)-20-O-acetylingenol
- The dosage-toxicity-efficacy relationship of kansui and licorice in malignant pleural effusion rats based on factor analysis
- Restoration of Intestinal Mucosa in Euphorbia kansui-treated Severe Acute Pancreatitis Rats based on HMGB1/MFG-E8 Expression
Other / unclassified
0
Verified: design read from PubMed for a DOI that resolves to the cited paper Unverified: taken from the study's recorded description
Clinical Studies
Effects of euphorbia kansui on the serum levels of IL-6, TNF-α, NF-κB, sTNFR and IL-8 in patients with severe acute pancreatitis
Thirty-six patients admitted to a single Chinese hospital with severe acute pancreatitis between March 2017 and May 2018 were randomly allocated to two groups, matched at baseline for age, sex, precipitant, Balthazar CT score and APACHE II score. Serum TNF-alpha, sTNFR, NF-kB, IL-6 and IL-8 measured by ELISA at successive time points were lower with Euphorbia kansui, and the authors attributed this to inhibition of NF-kB activation. This is the only human trial found for the herb; it is small, single-centre, and reports surrogate cytokine endpoints rather than mortality, organ failure or length of stay, so it should not be read as establishing clinical benefit.
Toxicity Reduction of Euphorbia kansui Stir-Fried with Vinegar Based on Conversion of 3-O-(2′E,4′Z-Decadi-enoyl)-20-O-acetylingenol
Vinegar stir-frying reduced the content of the toxic diterpenoid 3-O-(2'E,4'Z-decadienoyl)-20-O-acetylingenol and raised that of ingenol. In zebrafish embryos the parent diterpenoid had an LC50 of 0.412 micrograms per millilitre against greater than 100 micrograms per millilitre for ingenol, and caused reduced heart rate, pericardial oedema and impaired gastrointestinal motility via oxidative damage, inflammation and apoptosis, effects absent with ingenol. This is the mechanistic basis for the rule that Gan Sui is processed before internal use.
The dosage-toxicity-efficacy relationship of kansui and licorice in malignant pleural effusion rats based on factor analysis
Malignant pleural effusion rats received kansui and licorice at ratios of 4:1, 2:1, 1:1, 0.5:1, 0.25:1 and 0.1:1, with furosemide as positive control. Factor analysis of eight toxicity and five efficacy indices showed toxicity increasing and efficacy decreasing as the licorice dose rose, with the inflection between the 2:1 and 1:1 ratios. Kansui alone was effective against the effusion; adding licorice weakened it and, at some ratios, caused serious toxicity. This is direct experimental support for the classical prohibition on combining the two.
Restoration of Intestinal Mucosa in Euphorbia kansui-treated Severe Acute Pancreatitis Rats based on HMGB1/MFG-E8 Expression
In a rat model of severe acute pancreatitis, Euphorbia kansui treatment was associated with restoration of intestinal mucosa, examined through HMGB1 and MFG-E8 expression. It offers a mechanistic rationale for the traditional purgative approach to pancreatitis with intestinal failure, at animal level only.
⚠ Safety & Contraindications
- Pregnancy
- Liver conditions
- Kidney conditions
- Toxic — professional use only
Contraindications
Contraindicated in pregnancy and in the weak or depleted.
Safety Warnings
- A drastic purgative used briefly and at small doses, usually as a powder rather than in decoction.
- Incompatible with Gan Cao (Radix Glycyrrhizae) under the classical eighteen incompatibilities.
⚠ Rule-Based Cautions
These entries come from the deterministic rule tables that gate Verscienta's formula tools — classical pair prohibitions, pregnancy and lactation contraindications, and dose ceilings.
Incompatibilities (十八反 / 十九畏)
- 十八反: Gan Cao × Gan Sui — avoid combining with Gan Cao / Glycyrrhiza / Licorice
Pregnancy
Avoid toxic purgative
⚠ Toxicity Information
Violent purgation with watery diarrhoea, abdominal colic, vomiting and dehydration; the latex blisters skin and inflames the eye.
Historical Texts
Shen Nong Ben Cao Jing
Han dynastyShang Han Lun and Jin Gui Yao Lue
Han dynastyReferences
- Wu Tian-Shung; Lin Yuh-Meei; Haruna Mitsumasa; Pan De-Ji; Shingu Tetsuro; Chen Yuh-pan; Hsu Hong-Yen; Nakano Tatsuhiko; Lee Kuo-Hsiung. Antitumor Agents, 119. Kansuiphorins A and B, Two Novel Antileukemic Diterpene Esters from Euphorbia kansui . Journal of Natural Products (1991) [DOI]
- Shu Xin; Jiang Xi-Wen; Cheng Brian Chi-Yan; Ma Shuang-Cheng; Chen Guang-Ying; Yu Zhi-Ling. Ultra-performance liquid chromatography-quadrupole/time-of-flight mass spectrometry analysis of the impact of processing on toxic components of Kansui Radix . BMC Complementary and Alternative Medicine (2016) [DOI]
- Shen Juan; Pu Zong-Jin; Kai Jun; Kang An; Tang Yu-Ping; Shang Li-Li; Zhou Gui-Sheng; Zhu Zhen-Hua; Shang Er-Xin; Li Shao-Ping; Cao Yu-Jie; Tao Wei-Wei; Su Shu-Lan; Zhang Li; Zhou Huiping; Qian Da-Wei; Duan Jin-Ao. Comparative metabolomics analysis for the compatibility and incompatibility of kansui and licorice with different ratios by UHPLC-QTOF/MS and multivariate data analysis . Journal of Chromatography B (2017) [DOI]
- Truong Minh-Nhut; Duong-Thi Ngoc-Lan; Vo Trong-Tuan; Le-Thi Lan-Phuong. The Antagonistic Interactions Between Traditional Medicine Herbs and Licorice: A Non-Systematic Review . Natural Product Communications (2025) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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