Dong Gua Pi
StarBenincasa hispida (Thunb.) Cogn.
Traditionally used for
- Cough & breathing
- Digestion
- Urinary & fluids
- Skin
Cautions & contraindications
- Allergy risk
☯ TCM Properties
Promotes Urination and Reduces Edema; Clears Heat and Resolves Summer-Heat; Clears Damp-Heat from the Lower Burner
Traditional Chinese Uses
Dong Gua Pi (winter melon rind) is a cool, sweet herb used in Chinese medicine to drain Dampness and promote urination, with a focused action on reducing edema of the skin and subcutaneous tissues. It is particularly useful for general puffiness of the limbs and face from Lung and Stomach Qi failing to distribute fluids, and for summer-heat conditions with thirst and scanty urination. Its action is gentler than the seed and has a more surface-directed effect.
Western Herbalism Properties
Relationships
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Botanical Description
Benincasa hispida, the wax gourd or winter melon, is a vigorous annual trailing or climbing vine in the Cucurbitaceae, with long, ridged, hairy stems bearing branched tendrils. The large alternate leaves are palmately five- to seven-lobed, rough-hairy on both surfaces. Solitary yellow funnel-shaped flowers are produced in leaf axils; the plant is monoecious. The fruit is a very large oblong to nearly spherical pepo, 30-80 cm long, with bristly young surface that matures to a smooth pale green skin coated with a thick whitish waxy bloom, giving the common name. The white juicy flesh contains many flat seeds. The dried outer peel (rind) of the mature fruit, removed in thin strips after the flesh is used as food, is the medicinal Dong Gua Pi.
Active Constituents
Isovitexin
Flavone C-glycoside (apigenin 6-C-glucoside)Concentration: 4.798 mg/g of the peel drug, the most abundant of the eight compounds quantified by HPLC-PDA in Benincasae Exocarpium
The most abundant quantified flavonoid of the peel. In bioassay-guided work on the peel it was one of five flavonoids that inhibited advanced glycation end-product formation more strongly than the positive controls, which is the mechanistic basis usually offered for the peel's use in diabetic complications. In vitro only.
Vitexin-2''-O-rhamnoside
Flavone C-glycoside (acylated vitexin glycoside)Concentration: 3.780 mg/g of the peel drug by HPLC-PDA
Second most abundant quantified flavonoid of the peel and the compound with the highest alpha-glucosidase inhibitory activity in the isolation study, outperforming the reference drug in that assay. It also inhibited advanced glycation end-product formation.
Protocatechuic acid
Phenolic acid (dihydroxybenzoic acid)Concentration: 1.260 mg/g of the peel drug by HPLC-PDA
A phenolic acid of the peel that showed significant inhibition of advanced glycation end-product formation in specific assay systems. It is widespread in plants and is not a marker for this drug.
Orientin
Flavone C-glycoside (luteolin 8-C-glucoside)Concentration: 1.115 mg/g of the peel drug by HPLC-PDA
One of the flavone C-glycosides quantified in the peel and among the flavonoids active against advanced glycation end-product formation in vitro.
Vitexin-4''-O-glucoside
Flavone C-glycosideConcentration: 0.909 mg/g of the peel drug by HPLC-PDA
A minor vitexin derivative of the peel, active in the anti-glycation assay alongside the other flavonoids of this group.
Caffeic acid
Hydroxycinnamic acidConcentration: 0.790 mg/g of the peel drug by HPLC-PDA
A common phenolic acid of the peel with anti-glycation activity in the isolation study. Its presence says nothing distinctive about this drug's identity.
Vitexin
Flavone C-glycoside (apigenin 8-C-glucoside)Concentration: 0.768 mg/g of the peel drug by HPLC-PDA
The parent aglycone-glycoside of the vitexin series found in the peel, present at lower levels than its rhamnoside and glucoside derivatives. Active against advanced glycation end-product formation in vitro.
Gallic acid
Phenolic acid (trihydroxybenzoic acid)Concentration: 0.572 mg/g of the peel drug by HPLC-PDA
The least abundant of the eight quantified peel constituents; contributed anti-glycation activity in specific assay systems.
Triterpenols and triterpenol acetates of the epicuticular wax
Triterpenoid alcohols and their acetate estersConcentration: Over 61% of the surface wax crystals of the fruit, the remainder being very-long-chain aliphatics
These make up the white wax bloom that gives wax gourd its name and that sits on the outer surface of the drug. They are a defining feature of the peel and are absent from the seed drug. Their function described in the source work is protective for the plant; no pharmacology has been attributed to them in this drug.
Peel alkaloid fraction (including ningpeisinoside, lobelanine and kukoamine A)
Alkaloids (heterocyclic and non-heterocyclic)Concentration: Eleven alkaloids among the 43 compounds so far isolated from the peel drug; no quantitative standard established
An under-characterised class in this drug. They are recorded in the phytochemical review of Benincasae Exocarpium but have not been individually assayed from this source, so no activity should be attributed to them here.
Soluble dietary fibre and peel polysaccharides
Polysaccharide (soluble fibre)Concentration: A substantial fraction of the dried peel; sugars reported include galactose, glucose, xylose and sorbose
The bulk carbohydrate fraction of the peel. It is the constituent most plausibly behind the traditional bland, water-moving character of the drug, but it has not been separately tested for the diuretic effect.
⚠ Drug Interactions
Loop and thiazide diuretics
Promoting urination is the primary recorded action of this drug and the diuretic effect has been reported since it was first entered in the materia medica. Modern support is indirect: a compound Chinese herbal tea containing the peel significantly increased 24 h urine volume in rats (28.4 +/- 8.9 mL/d versus 20.7 +/- 5.6 mL/d in controls, p < 0.001), and Chinese clinical reports describe decoctions of the peel resolving oedema in nephrotic syndrome faster than conventional care. No head-to-head pharmacokinetic or pharmacodynamic study with a diuretic drug exists.
Clinical note: In patients already on a diuretic, expect additive fluid loss. Monitor weight, blood pressure and serum potassium and sodium when the herb is added, particularly in elderly patients and those with cardiac or renal disease.
Urate-lowering drugs (allopurinol, febuxostat, uricosurics)
In hyperuricaemic rats the peel drug lowered serum uric acid, inhibited hepatic xanthine oxidase (a moderate effect, IC50 720.6 µg/mL in vitro) and altered renal expression of URAT1, GLUT9, ABCG2 and OAT1, promoting urate excretion while reducing reabsorption. It also lowered AST, creatinine and blood urea nitrogen and damped TLR4/NF-kB/NLRP3 renal inflammation. Because allopurinol and febuxostat act on xanthine oxidase and uricosurics act on URAT1, the overlap is direct in mechanism. This is a rat study; the transporters involved (notably OAT1 and ABCG2) also handle many drugs, and that has not been studied at all for this herb.
Clinical note: In gout patients on urate-lowering therapy, monitor serum urate when the herb is used regularly rather than assuming no effect. Do not treat it as a substitute for urate-lowering therapy.
Oral hypoglycaemics and insulin
Bioassay-guided isolation from the peel found flavonoids that inhibit alpha-glucosidase and advanced glycation end-product formation in vitro, with vitexin-2''-O-rhamnoside outperforming the reference alpha-glucosidase inhibitor. The one human study of the species used a powdered drink containing 2.5 g of Benincasa hispida aqueous extract for 12 weeks in 50 people with type 2 diabetes and reported a greater fall in fasting plasma glucose in the intervention group, though the confidence interval crossed zero. That trial did not state which plant part the extract came from, so it cannot be read as evidence for the peel specifically.
Clinical note: Where a diabetic patient takes this herb regularly alongside a sulfonylurea, insulin or an alpha-glucosidase inhibitor such as acarbose, ask about hypoglycaemic symptoms and check home glucose readings rather than assuming the herb is inert.
Antihypertensive drugs
In the 12-week human study of a Benincasa hispida powdered drink in type 2 diabetes, diastolic blood pressure fell by 7.0 mmHg (95% CI -11.4 to -2.5) in the intervention group. Separately, Benincasa hispida extract altered renal metabolomic profiles and reduced hypertension measures in Dahl salt-sensitive rats. Neither study identified the plant part as the peel, and the diuretic action of the peel provides a second, independent route to blood-pressure lowering.
Clinical note: Check blood pressure when the herb is started in a treated hypertensive patient, especially where a diuretic is part of the regimen.
Ragweed pollen allergen immunotherapy, and ragweed-sensitised patients generally
A published paediatric case documents anaphylaxis to winter melon (Benincasa hispida) attributed to cross-reactivity with ragweed pollen sensitisation. This is a genuine, if rare, IgE-mediated hazard rather than a pharmacokinetic interaction, and it applies to the plant material as a whole, including the peel. Absence of a formal incidence figure is not evidence that the risk is negligible.
Clinical note: Ask about ragweed pollinosis and cucurbit food allergy before prescribing this herb. In a patient with known ragweed sensitisation, avoid it or introduce it only with an anaphylaxis plan in place.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 9–30 g | Daily | — | — | 中国药典 2020 【用法与用量】9～30g。 【性味与归经】甘，凉。归脾、小肠经。 — Chinese Pharmacopoeia 2020, quoted verbatim; route and cautions preserved. Replaces a cleared category-filler value. |
Evidence Tier
Moderate evidence · 6 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
5
2 verified · 3 unverified
Show 5 studies
- Antihyperuricemic, hepatoprotective and nephroprotective roles of Benincasae Exocarpium in hyperuricemia rats
- Isolation of Anti-Diabetic Active Compounds from Benincasae Exocarpium and Development of Simultaneous Analysis by HPLC-PDA
- Chemical compositions and cryo-adhesive probing of the epicuticular wax crystals on fruit surface of wax gourd (Benincasa hispida)
- Acute and sub-chronic toxicity studies of Benincasa hispida (Thunb.) cogniaux fruit extract in rodents
- Influence of Benincasa hispida Peel Extracts on Antioxidant and Anti-Aging Activities, including Molecular Docking Simulation
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
Antihyperuricemic, hepatoprotective and nephroprotective roles of Benincasae Exocarpium in hyperuricemia rats
The peel drug was profiled by UPLC-MS/MS (amino acids, flavonoids, alkaloids and terpenoids) and tested in rats made hyperuricaemic with potassium oxonate and hypoxanthine. It moderately inhibited xanthine oxidase in vitro (IC50 720.6 µg/mL) and in vivo lowered serum uric acid, total cholesterol, triglycerides, IL-1beta, IL-6, TNF-alpha, AST, creatinine and blood urea nitrogen. Transcriptomics with Western blot confirmed regulation of hepatic XOD and renal URAT1, GLUT9, ABCG2 and OAT1, damping of TLR4/NF-kB/NLRP3 renal inflammation, and hepatic IRS2/FoxO1/AMPK/ACC signalling. Rats only, and the drug studied was explicitly the peel.
Isolation of Anti-Diabetic Active Compounds from Benincasae Exocarpium and Development of Simultaneous Analysis by HPLC-PDA
Bioassay-guided isolation from the fruit peel yielded eleven compounds: p-hydroxybenzoic acid, protocatechuic acid, isovanillin, 5-hydroxymethylfurfural, isovitexin, vitexin, orientin, gallic acid, caffeic acid, vitexin-2''-O-rhamnoside and vitexin-4''-O-glucoside. Eight showed significant activity against advanced glycation end-product formation or alpha-glucosidase, the flavonoids most strongly, with vitexin-2''-O-rhamnoside the best alpha-glucosidase inhibitor. An HPLC-PDA method quantified eight of them, giving the only published content figures specific to this drug. In vitro throughout.
Efficacy of a Benincasa hispida powdered drink in improving metabolic control in patients with type 2 diabetes: A placebo-controlled study
Fifty adults with type 2 diabetes were randomised to a powdered drink containing 2.5 g of Benincasa hispida aqueous extract or control for 12 weeks. Diastolic blood pressure fell significantly in the intervention group (-7.0 mmHg, 95% CI -11.4 to -2.5), fasting plasma glucose fell more in the intervention than the control group without reaching significance, and lean body mass trended up. The report does not state which plant part the extract was made from, so it is evidence for the species rather than specifically for the peel drug; the analysis was also within-group paired testing rather than between-group.
Chemical compositions and cryo-adhesive probing of the epicuticular wax crystals on fruit surface of wax gourd (Benincasa hispida)
Characterisation of the white wax bloom on the fruit surface, which is part of the peel drug and the origin of the name wax gourd. Rodlet, platelet, fragment and granule crystalloids form a fine film over the fruit; triterpenols and triterpenol acetates made up over 61% of the crystals, followed by very-long-chain aliphatics. Relevant to identity and to the fact that the peel carries a chemistry the seed does not.
Acute and sub-chronic toxicity studies of Benincasa hispida (Thunb.) cogniaux fruit extract in rodents
A standardised 70% ethanolic extract of Benincasa hispida fruit pulp caused no mortality or behavioural toxicity at the 2000 mg/kg OECD limit dose in mice, and 90 days of dosing at 40, 200 and 1000 mg/kg in Wistar rats produced no significant change in intake, body or organ weights, haematology, serum biochemistry, urinalysis or histopathology. Note the plant part: this is fruit pulp, not the peel drug, so it bounds the safety of the species but not of Benincasae Exocarpium specifically.
Influence of Benincasa hispida Peel Extracts on Antioxidant and Anti-Aging Activities, including Molecular Docking Simulation
Peel-specific extracts were assessed for antioxidant capacity and for inhibition of skin-ageing-associated enzymes, supported by molecular docking. The work is aimed at topical and cosmetic application and adds to the in vitro profile of the peel, but carries no implications for oral dosing.
⚠ Safety & Contraindications
- Allergy risk
Contraindications
Its use is cautious in patients with puffiness caused by malnutrition.
Source: Xi S, Gong Y. Essentials of Chinese Materia Medica and Medical Formulas. Academic Press/Elsevier, 2017, pp. 139–143.
Historical Texts
Kai Bao Ben Cao (Materia Medica of the Kaibao Reign)
Northern Song, 973-974 CEChinese clinical and case-record literature on Dong Gua Pi, summarised in the modern review of Benincasae Exocarpium
Twentieth century to presentPlant-part distinction between Dong Gua Pi (Exocarpium Benincasae) and Dong Gua Zi (Semen Benincasae)
Established in Chinese materia medica practice and carried into the current Chinese PharmacopoeiaReferences
- Zhang M; Lei J; Wang Y; Zhang J; Liu D. Ethnopharmacology, phytochemistry and pharmacology of Benincasae Exocarpium: A review . Chinese Herbal Medicines (2023) [DOI]
- Mao Q; Zhai X; Yan J; Liu W; Sun P; Zhou Q; Jiang B. Medicinal Ingredients of Wax Gourd (Benincasa hispida (Thunb.) Cogn.): An Integrated Review of Phytochemistry, Pharmacology, and Nutraceutical Applications . Plants (2026) [DOI]
- Nagakura KI; Takei M; Sato S; Yanagida N; Ebisawa M. Anaphylaxis to winter melon due to cross-reactivity of sensitization to ragweed pollen . Pediatric Allergy and Immunology (2022) [DOI]
- Ahmad H; Zhao X; Ahmad N; Khan A; Jin Y; Du J; Zheng X; Zeng L; Ouyang Y; Yang P; Chen M; Li X; Yang Z; Tian Z. Benincasa hispida extracts positively regulated high salt-induced hypertension in Dahl salt-sensitive rats: Impact on biochemical profile and metabolic patterns . Journal of Food Biochemistry (2022) [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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