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Scientific Name(s): Cucurbita pepo L.
Common Name(s): Acorn squash, Butternut squash, Chilacayote, Field pumpkin, Fig-leaf gourd, Pepo, Pumpkin, Squash, Yellow summer squash, Zucchini

Clinical Overview


Pumpkin seeds, seed oil, and pumpkin pulp have been evaluated in limited clinical trials for medicinal actions, including anthelmintic, hypotensive, and hypoglycemic activity. The extracts may also be useful for managing symptoms of benign prostatic hyperplasia and anxiety-related disorders, although limited clinical trial information is available.


Limited high-quality clinical trials exist to support therapeutic dosing. Pumpkin seed 30 g daily has been used as a source of supplemental iron in nonpregnant adults.


Contraindications have not been identified.


Information regarding safety and efficacy in pregnancy and lactation is lacking. Antinutrients (eg, oxalates, cyanide, tannin) have been identified in pumpkin seeds and leaves.


An increased anticoagulant effect of warfarin has been reported during concurrent ingestion of a combination preparation of cucurbita, saw palmetto, and vitamin E. Causality of cucurbita was not proven.

Adverse Reactions

Clinical trials report few adverse reactions. Methemoglobinemia caused by high nitrate content has been reported in infants given zucchini soup for constipation. IgE-related allergy to zucchini has been reported, as well as oral allergy syndrome, nausea, diarrhea, and pruritus. Cross-reactivity to watermelon, cucumber, and pumpkin was demonstrated.


There have been no reports of severe toxicity with the use of cucurbita extracts. Antinutrients have been described in the seeds and leaves, including oxalates, tannins, and cyanide.


Pumpkin is a dicotyledonous vegetable that develops long vine-like stems with trifoliate leaves and edible large, fleshy fruits. The rapid-growing plant can climb to 5 m. The large, yellow flowers are eaten in some Mediterranean and Mexican cultures, and the fruits are eaten worldwide. Many cultivated varieties can be found throughout the world.1, 2, 3 Other members of the genus include Cucurbita digitata, Cucurbita ficifolia, and Cucurbita maxima species.


The seeds of several species of pumpkin have been used in traditional medicine for centuries. Traditionally, the seeds of the Cucurbita species are ingested as a tea or after grinding. They have been used to immobilize and aid in the expulsion of intestinal worms and parasites. In some cultures, small amounts of the seeds are eaten on a daily basis as a prophylactic against worm infections. The seeds also have been used in the treatment of prostate disorders. Pumpkin flowers are sometimes added to tacos or soup as a source of protein.2, 3, 4


The fleshy pulp of Cucurbita is primarily consumed as a vegetable. Investigational interest centers on polysaccharide and pectin content, as well as the presence of triterpenoids, cucurbitan glycosides, carotenoids, including lutein and beta-carotene, and cucurmosin, a ribosome-inactivating protein.3, 5, 6, 7, 8, 9, 10, 11

The pumpkin flower is a source of protein. Glutamic and aspartic acid, leucine, valine, phenylalanine, and tryptophan are among the amino acids identified. Phytosterols, such as spinasterol, have been identified, as well as trypsin-inhibitors.4, 12, 13

Lipids comprise up to 50% of the seed and around 30% is protein. Pumpkin seeds can be a nutritional source of iron and potassium. Phytosterols (eg, beta-sitosterol, stigmasterol), antioxidant tocopherols, antihelminthic cucurbitin, squalene, and cardioprotective fatty acids have been isolated from the seeds and seed oil. The presence of squash inhibitors (serine protease inhibitors) is thought to confer a protective effect to the plant against pests and pathogens.3, 14, 15, 16, 17, 18, 19, 20

Uses and Pharmacology

Anthelmintic activity

Animal data

In vitro experiments and animal studies have demonstrated anthelmintic action of dried seeds and extracts against some Schistosoma japonicum and malarial parasites, but not all parasites (eg, tapeworm).21, 22, 23

Clinical data

A preclinical study demonstrated an anthelmintic effect with pumpkin seed 23 g in 100 mL water; however, cucurbitin has been generally supplanted by more effective single-dose vermifuges.3

Benign prostatic hyperplasia (BPH)

Pumpkin seed extract may have antiandrogenic and anti-inflammatory activity.24

Animal data

A protective effect on testosterone-induced prostatic hyperplasia was seen in rats fed pumpkin seed oil.25

Clinical data

Trials are limited and the results conflict. A large clinical trial (N = 476) found an improvement in symptoms associated with BPH as determined by the International Prostate Symptom Score (IPSS), but no change in objective measures, such as p-vol or post-void residual urine.24 Another clinical trial found that a preparation of C. pepo (curbicin) improved certain parameters of BPH, including urinary flow, micturition time, residual urine, and urinary frequency versus placebo.26 A sponsor-funded phase 2 placebo-controlled, randomized clinical trial (n = 57) conducted in men with benign prostatic hypertrophy (BPH) found a commercially available herbal formulation containing pumpkin seed oil, lycopene, saw palmetto, pygeum, and Epilobium parviflorum to significantly reduce median prostate specific scores as well as day time and night time urinary frequency. Improvements were progressive and were observed in several scores at 1 month and in all scores at 3 months.45 IPSS was not shown to differ among 1,431 men with BPH-related lower urinary tract infections randomized to be treated for 12 months with pumpkin seed 5 g twice daily, pumpkin seed extract 500 mg twice daily, or placebo. All individual symptoms improved in all groups; no clinically significant changes in prostate volume, post-void residual volume, or prostate-specific antigen levels were observed.48


Limited in vitro and animal experiments have shown antimutagenic and inhibitory actions of pumpkin seed extract and boiled, but not fresh, pumpkin juice.3, 27, 28

Cardiovascular effects

In rats, pumpkin seed oil improved the plasma lipid profile3, 29 and exhibited antioxidant activity in the heart and liver.30 In these experiments, a hypotensive action was demonstrated by the oil alone, and in combination with captopril and felodipine.29, 30


Defatted squash seed is rich in tryptophan.31, 32 Limited clinical trials have been conducted comparing plant-based tryptophan with the pharmaceutical grade chemical. Modest improvements were demonstrated in social anxiety disorder (social phobia) and insomnia when squash-derived tryptophan was administered with glucose to improve CNS blood levels.31, 32


Animal data

The pulp and seeds of C. ficifolia have been evaluated for hypoglycemic action in alloxan-induced diabetic rabbits.3, 33

Clinical data

Multiple open-label clinical studies report reduced postprandial serum and fasting glucose levels in patients with type 2 diabetes given pumpkin juice or pumpkin powder, but quality clinical trials are lacking.3 A small clinical trial (N = 10) demonstrated decreases in fasting blood glucose levels 3 to 5 hours after consumption of the juice of fresh immature C. ficifolia fruit; 4 mL/kg of body weight of the juice was administered (100 g crushed fruit was equivalent to 75 mL of juice).34 A cross-sectional and follow-up dietary intervention study in hemodialysis patients (n = 30) documented significantly improved blood pressure, total cholesterol, triglyceride/HDL cholesterol ratio, serum triglycerides, glucose tolerance, serum fatty acid composition, and inflammatory markers (ie, interleukin [IL]-6, tumor necrosis factor [TNF]-alpha, high-sensitivity C-reactive protein [hs-CRP]) after 12 weeks of dietary supplementation with 30 g/day of a milled flax-sesame-pumpkin seed (3:1:1) mixture added to 200 mL of fat-free milk before dinner. Pruritis also improved in all patients.46

Other uses

Lower urinary tract symptoms

The European Association of Urology guidelines on the management of lower urinary tract symptoms (LUTS) in males (2013) discuss but do not make any specific recommendations on phytotherapy for the treatment of male LUTS because of variability of products, lack of regulatory infrastructure, and variability in methodologies in the available literature. C. pepo (pumpkin seeds) is recognized as one of the most widely used plants.44


Limited high-quality clinical trials exist to support therapeutic dosing. Fresh pumpkin juice 4 mL/kg of body weight was administered in a study conducted among patients with type 2 diabetes.34 However, it would take 100 g of crushed fruit to equal 75 mL of juice.35 Pumpkin seed 30 g provide approximately 4 mg of iron. When administered to nonpregnant adults for 4 weeks, iron status improved.14 Pumpkin seed 23 g per 100 mL was used in a study of anthelmintic action.3

Pregnancy / Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking. Anti-nutrients (eg, oxalates, cyanide, tannin) have been identified in pumpkin seeds and leaves, with detrimental effects on growing rats and chickens.3, 19


In an experiment conducted in rats, pumpkin seed oil potentiated the hypotensive effect of captopril and felodipine.30 Two men stabilized on warfarin experienced an increase in the international normalized ratio (INR) after taking an herbal combination containing Cucurbita, saw palmetto, and vitamin E.36 In both patients, the INR returned to previous values when the herbal product was discontinued. Although neither Cucurbita nor saw palmetto can be ruled out as the cause of the INR increase, it is more likely that vitamin E interfered with vitamin K-dependent clotting factors, adding to the anticoagulant effects of warfarin.36

Adverse Reactions

Clinical trials report few adverse reactions.3, 26

Methemoglobinemia has been reported in infants 2 months of age or younger who were given zucchini soup for constipation. The adverse reaction was attributed to the high nitrate content of the vegetable.37 The importance of considering cross-contamination between foods grown in the same fields was demonstrated when hemolytic crisis was reported in an 8-month-old infant with undiagnosed glucose-6-phosphate dehydrogenase (G6PD) deficiency after eating pumpkin for the first time. DNA analysis of the pumpkin sample revealed it was cross-contaminated with fava bean DNA; the hemolytic reaction was attributed to substances present in the fava beans that are known to trigger hemolytic crisis, especially in children with G6PD deficiency.47

Vitamin A toxicity, with abnormal liver function tests, has been reported with prolonged and excessive pumpkin consumption.38

IgE-related allergy to zucchini has been reported. Oral allergy syndrome, nausea, diarrhea, and pruritus have also been described in a number of patients. Cross-reactivity to watermelon, cucumber, and pumpkin has occurred.39, 40, 41

A number of pathogenic fungi causing the deterioration of carved pumpkins have been identified. These fungi could cause severe infection in immunocompromised individuals.42


Severe toxicity has not been reported with the use of Cucurbita extracts. Ingestion of C. maxima seeds by rats and pigs during a 4-week period resulted in no changes in most laboratory parameters.43 The median lethal dose of freeze-dried C. ficifolia juice in mice was 650 mg/kg.35

Antinutrients (eg, oxalates, cyanide, tannin) have been found in pumpkin seeds and leaves, having detrimental effects on rats and chickens.3, 19 Trypsin inhibitors have been described in flowers of pumpkin varieties, but were not considered antinutritional.4


1. Curcurbita pepo L. USDA, NRCS. 2007. The PLANTS Database (, July, 2009). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
2. Tyler VE. The New Honest Herbal. 2nd ed. Philadelphia, PA: GF Stickley Co; 1987.
3. Caili F, Huan S, Quanhong L. A review on pharmacological activities and utilization technologies of pumpkin. Plant Foods Hum Nutr. 2006;61(2):73-80.16758316
4. Sotelo A, López-García S, Basurto-Peña F. Content of nutrient and antinutrient in edible flowers of wild plants in Mexico. Plant Foods Hum Nutr. 2007;62(3):133-138.17768684
5. Wang DC, Xiang H, Li D, et al. Purine-containing cucurbitane triterpenoids from Cucurbita pepo cv dayangua. Phytochemistry. 2008;69(6):1434-1438.18325551
6. Nayab D, Ali D, Arshad N, Malik A, Choudhary MI, Ahmed Z. Cucurbitacin glucosides from Citrullus colocynthis. Nat Prod Res. 2006;20(5):409-413.16644537
7. Hou X, Meehan EJ, Xie J, Huang M, Chen M, Chen L. Atomic resolution structure of cucurmosin, a novel type 1 ribosome-inactivating protein from the sarcocarp of Cucurbita moschata. J Struct Biol. 2008;164(1):81-87.18652900
8. Arima HK, Rodríguez-Amaya DB. Carotenoid composition and vitamin A value of a squash and a pumpkin from northeastern Brazil. Arch Latinoam Nutr. 1990;40(2):284-292.2133187
9. Barua S, et al. Studies on dark green leafy vegetables and yellow vegetables. Part 5. Availability of carotene as a source of vitamin A. Bangladesh Pharm J. 1977;6:8-12.
10. Stoianova-Ivanova B, et al. Long chain hydrocarbons and fatty acids in different parts of the fruits of Cucurbita maxima linnaeus. Riv Ital Essenze Profumi Piante Officinali Aromi Saponi Cosmetici Aerosol. 1975;57:377-382.
11. Jaroniewska D, et al. Vegetables in diet and treatment: pumpkin. Farm Pol. 1997;53(3):134-135.
12. Villaseñor IM, Lemon P, Palileo A, Bremner JB. Antigenotoxic spinasterol from Cucurbita maxima flowers. Mutat Res. 1996;360(2):89-93.8649469
13. Itokawa H, et al. Studies on the constituents of the male flowers of Cucurbita pepo L [in Japanese]. Yakugaku Zasshi J Pharm Soc Japan. 1982;102(4):318-321.
14. Naghii MR, Mofid M. Impact of daily consumption of iron fortified ready-to-eat cereal and pumpkin seed kernels (Cucurbita pepo) on serum iron in adult women. Biofactors. 2007;30(1):19-26.18198398
15. Ryan E, Galvin K, O'Connor TP, Maguire AR, O'Brien NM. Phytosterol, squalene, tocopherol content and fatty acid profile of selected seeds, grains, and legumes. Plant Foods Hum Nutr. 2007;62(3):85-91.17594521
16. Stevenson DG, Eller FJ, Wang L, Jane JL, Wang T, Inglett GE. Oil and tocopherol content and composition of pumpkin seed oil in 12 cultivars. J Agric Food Chem. 2007;55(10):4005-4013.17439238
17. Krauze-Baranowska M, Cisowski W. Flavonols from Cucurbita pepo L. herb. Acta Pol Pharm. 1996;53(1):53-56.
18. Chiche L, Heitz A, Gelly JC, et al. Squash inhibitors: from structural motifs to macrocyclic knottins. Curr Protein Pept Sci. 2004;5(5):341-349.15551519
19. Akwaowo EU, Ndon BA, Etuk EU. Minerals and antinutrients in fluted pumpkin (Telfairia occidentalis Hook f.). Food Chem. 2000;70(2):235-240.
20. Wong CM, Yeung HW, Ng TB. Screening of Trichosanthes kirilowii, Momordica charantia and Cucurbita maxima (family Cucurbitaceae) for compounds with antilipolytic activity. J Ethnopharmacol. 1985;13(3):313-321.4058034
21. De Amorim A, et al. Anthelmintic action of plants. Part 6. Influence of pumpkin seeds in the removal of Vampirolepis nana from mice. Rev Bras Farmacogn. 1992;73:81-82.
22. Elisha E, et al. Anthelmintic activity of some Iraqi plants of the Cucurbitaceae. Pharm Biol. 1987;25(3):153-157.
23. Amorim CZ, Marques AD, Cordeiro RS. Screening of the antimalarial activity of plants of the Cucurbitaceae family. Mem Inst Oswaldo Cruz. 1991;86(suppl 2):177-180.1841996
24. Dreikorn K. The role of phytotherapy in treating lower urinary tract symptoms and benign prostatic hyperplasia. World J Urol. 2002;19(6):426-435.12022711
25. Gossell-Williams M, Davis A, O'Connor N. Inhibition of testosterone-induced hyperplasia of the prostate of sprague-dawley rats by pumpkin seed oil. J Med Food. 2006;9(2):284-286.16822218
26. Carbin B, Larsson B, Lindahl O. Treatment of benign prostatic hyperplasia with phytosterols. Br J Urol. 1990;66(6):639-641.1702340
27. Rojas NM, Acosta S. Antitumoral potential of aqueous extracts of Cuban plants. Part 2. Rev Cubana Farm. 1980:14:219-225.
28. Jayaprakasam B, Seeram NP, Nair MG. Anticancer and antiinflammatory activities of cucurbitacins from Cucurbita andreana. Cancer Lett. 2003;189(1):11-16.12445672
29. Gossell-Williams M, Lyttle K, Clarke T, Gardner M, Simon O. Supplementation with pumpkin seed oil improves plasma lipid profile and cardiovascular outcomes of female non-ovariectomized and ovariectomized Sprague-Dawley rats. Phytother Res. 2008;22(7):873-877.18567058
30. Zuhair HA, Abd El-Fattah AA, El-Sayed MI. Pumpkin-seed oil modulates the effect of felodipine and captopril in spontaneously hypertensive rats. Pharmacol Res. 2000;41(5):555-563.10753555
31. Hudson C, Hudson S, MacKenzie J. Protein-source tryptophan as an efficacious treatment for social anxiety disorder: a pilot study. Can J Physiol Pharmacol. 2007;85(9):928-932.18066139
32. Hudson C, Hudson SP, Hecht T, MacKenzie J. Protein source tryptophan versus pharmaceutical grade tryptophan as an efficacious treatment for chronic insomnia. Nutr Neurosci. 2005;8(2):121-127.16053244
33. Roman-Ramos R, Flores-Saenz JL, Alarcon-Aguilar FJ. Anti-hyperglycemic effect of some edible plants. J Ethnopharmacol. 1995;48(1):25-32.8569244
34. Acosta-Patiño JL, Jiménez-Balderas E, Juárez-Oropeza MA, Díaz-Zagoya JC. Hypoglycemic action of Cucurbita ficifolia on Type 2 diabetic patients with moderately high blood glucose levels. J Ethnopharmacol. 2001;77(1):99-101.11483384
35. Andrade-Cetto A, Heinrich M. Mexican plants with hypoglycaemic effect used in the treatment of diabetes. J Ethnopharmacol. 2005;99(3):325-348.15964161
36. Yue QY, Jansson K. Herbal drug curbicin and anticoagulant effect with and without warfarin: possibly related to the vitamin E component. J Am Geriatr Soc. 2001;49(6):838.11454132
37. Savino F, Maccario S, Guidi C, Castagno E, Farinasso D, Cresi F, Silvestro L, Mussa GC. Methemoglobinemia caused by the ingestion of courgette soup given in order to resolve constipation in two formula-fed infants. Ann Nutr Metab. 2006;50(4):368-371.16809905
38. Nagai K, Hosaka H, Kubo S, Nakabayashi T, Amagasaki Y, Nakamura N. Vitamin A toxicity secondary to excessive intake of yellow-green vegetables, liver and laver. J Hepatol. 1999;31(1):142-148.10424294
39. Reindl J, Anliker MD, Karamloo F, Vieths S, Wüthrich B. Allergy caused by ingestion of zucchini (Cucurbita pepo): characterization of allergens and cross-reactivity to pollen and other foods. J Allergy Clin Immunol. 2000;106(2):379-385.10932084
40. Figueredo E, Cuesta-Herranz J, Minguez A, et al. Allergy to pumpkin and cross-reactivity to other Cucurbitaceae fruits. J Allergy Clin Immunol. 2000;106(2):402-403.10932088
41. Potter T, Hashimoto K. Butternut squash (Cucurbita moschata) dermatitis. Contact Dermatitis. 1994;30(2):123.8187500
42. Nagano Y, Millar BC, Loughrey A, Goldsmith CE, Rooney PJ, Moore JE, Elborn JS. Jack o'Lantern–scarier than you think! Am J Infect Control. 2006;34(10):680-681.17161746
43. de Queiroz-Neto A, Mataqueiro MI, Santana AE, Alessi AC. Toxicologic evaluation of acute and subacute oral administration of Cucurbita maxima seed extracts to rats and swine. J Ethnopharmacol. 1994;43(1):45-51.7967649
44. Oelke M, Bachmann A, Descazeaud A, et al. EAU guidelines on the treatment and follow-up of non-neurogenic male lower urinary tract symptoms including benign prostatic obstruction. Eur Urol. 2013;64(1):118-40.23541338
45. Coulson S, Rao A, Beck SL, Steels E, Gramotnev H, Vitetta L. A phase II randomised double-blind placebo-controlled clinical trial investigating the efficacy and safety of ProstateEZE Max: a herbal medicine preparation for the management of symptoms of benign prostatic hypertrophy. Complement Ther Med. 2013;21(3):172-179.23642948
46. Ristic-Medic D, Perunicic-Pekovic G, Rasic-Milutinovic Z, et al. Effects of dietary milled seed mixture on fatty acid status and inflammatory markers in patients on hemodialysis. Scientific World Journal. 2014;22:563576.24578648
47. Zuccotti GV, Redaelli F, Gualdi V, et al. Hemolytic crisis in a G6PD-deficient infant after ingestion of pumpkin. Ital J Pediatr. 2014;40:71.25048416
48. Vahlensieck W, Theurer C, Pfitzer E, Patz B, Banik N, Engelmann U. Effects of pumpkin seed in men with lower urinary tract symptoms due to benign prostatic hyperplasia in the one-year, randomized, placebo-controlled GRANU study. Urol Int. 2015;94:286-295.25196580


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