Averrhoa carambola Linn.


Averrhoa pentandra Blanco

Vernacular Names:

Malaysia: Belimbing manis, belimbing persegi, belimbing sayur, belimbing batu, kembola, belimbing besi
English: Star fruit, five finger, five corner, country gooseberry
Chinese:  Yang ta’o
Javanese:  Blimbing alas, blimbing manis, blimbing legi, blimbing wana
Sundanese:  Balingbing, chalingching amis
Sumatran:  Balimbieng manih, balimbing manis
Thai:  Ma fueang
Tagalog:  Balimbing, balimbin, blimbing
Spanish:  Carambola, caramba[1]

General Information


Averrhoa carambola Linn. is a slow growing small tree, not more than 8 m tall, belonging to the family Oxalidaceae believed to originate from Sri Lanka and the Mollucas. It can be found widely spread in tropical countries. It is now widely cultivated in south-east Asia and Malaysia for its fruits.[2

The leaves are pinnate, about 15 cm long and the paired leaflets are smooth and ovate to ovate-lanceolate in shape. The panicles are small, axillary and bell-shaped, 5-6 mm long while the calyx is reddish purple. The petals are purple, often margined with white. The fleshy five-lobbed fruit, ovate to ellipsoidal, about 6 cm long with 5 longitudinal, sharp and angular lobes is attractive yellow-orange and pleasantly aromatic when ripe. The seeds are arillate.[3]

Plant Part Used

Fruit, leaf, shoot, flower, seeds.[1]

Chemical Constituents

Contents for every 100g edible portion: 35.7 calories; 0.38g proteins; 9.38g carbohydrates; 0.80-0.90g dietary fibre; 0.08 g Fat; 4.4-6.0mg Calcium; 0.32-1.65mg Iron; 2.35mg Potassium; 15.5-21.0mg Phosphorus. 26.0-53.1mg Ascorbic acid; 4.37mg tartaric acid; 9.6mg Oxalic acid; 2.2mg alpha-ketoglutaric acid; 1.32mg Citric acid.[4]

Traditional Use:

The fruits are used as a laxative, a refrigerant, an appetite stimulant, an antipyretic, a sialogogue, an astringent, an antiscorbutic, an antidysentery and an antiphlogistic. They have been used for the treatment of throat inflammation, mouth ulcers, toothache, cough,asthma, hiccups, tight feeling in chest, nausea, vomiting, indigestion, colic, diarrhoea, jaundice and ascites. It is claimed that they are effective as a remedy for bleeding haemorrhoids, haematemesis and melaena. They may be applied to wounds to arrest haemorrhages. The fruits are also used to treat rashes, pruritus, sunstroke, oliguria and strangury. The Chinese and Annamites apply the fruits in an eye-salve to treat eye-related diseases. They are used as a stimulant for the reproductive organs of both men and women. In women, the fruits can be used to increase lactation. In large doses, they can act as an emmenagogue and to induce abortion.[1]            

It can also be used to treat diabetics, to lower blood pressure, sore throat and as diuretic in kidney and bladder complaints.[2][5]

The crushed leaves or shoots are applied externally in the treatment of chickenpox, ringworms, tinea and headache. Tea of boiled leaves is also used to relieve aphthous stomatitis and angina. A mixture of the leaves and the fruits can be used to arrest vomiting and to treat fever.[1

The boiled flowers are used as an antihelmintic. The seed is used for asthma and colic.[3]

Pre-Clinical Data


Anti-inflammatory activity

In a study to investigate anti-inflammatory and bactericidal properties of an aqueous extract of the stem of Averrhoa carambola used as ethnomedicine for dysuria, it was found that it inhibits rat paw inflammation by carrageenin. Intraperitoneally, the A. carambola extract showed comparable anti-inflammatory effects to that of acetylsalicylic acid (ASA) at a dose of 300 mg/kg during the first hour and showing stronger activity over a longer duration of time.[6

Antibacterial activity

In the same study above, Averrhoa carambola exhibited antibacterial activity by inhibiting Staphylococcus aureus as indicated by a minimal bactericidal concentration (MBC) of 15.62 mg/ml or less. The extract from Averrhoa carambola also killed Klebsiella sp. (MBC value of 125 mg/mL).[6

Hypoglycaemic activity

Several insoluble fiber-rich fractions (insoluble dietary fiber, alcohol-insoluble solid and water-soluble solid) isolated from the pomace of Averrhoa carambola possessed potential hypoglycaemic effects as demonstrated by a study on several in vitro methods. The fibers could effectively absorb glucose, retard glucose diffusion, postpone the release of glucose from starch and inhibit a-amylase activity to certain extent.[7]  

Antioxidant activity

The analysis of polyphenolic antioxidants in star fruit by liquid chromatography and mass spectrometry was performed on the fruit juice and residue extract.[8] The peaks were mainly antioxidants which were mainly attributed to phenolic compounds. They were characterised as L-ascorbic acid, (-)epicatechin, gallic acid gallotannin forms and proanthocyanidins. The residue of the star fruit, which is normally discarded during juice drink processing, was further found to contain much higher antioxidant activity than the extracted juice. It is also showed strong antioxidant activity in delaying oxidative rancidity of soya bean oil at 110oC. This property of Averrhoa carambola residue extract powder would be of health benefit and suggests great commercial potential as nutraceutical resource or functional food ingredient.[9

Hypocholesterolaemic and hypolipidaemic activities

Water-insoluble fiber-rich fraction (WIFF) isolated from the pomace of star fruit showed hypocholesterolaemic and hypolipidaemic activities. Investigations in hamsters showed pronounced cholesterol- and lipid-lowering effects of WIFF which might be attributed to its ability to enhance the excretion of cholesterol and bile acids via the faeces. It decreases the serum concentrations of triacylglycerol, total cholesterol, liver cholesterol and increases the concentration of total lipids, cholesterol and bile acids in faeces.[10]


In preliminary investigations to characterize the hypothetical neurotoxin in the fruit, an extract, when injected in rats, provoked persistent convulsions.[11] Further study was conducted by chromatographic isolation of the convulsant fraction from the aqueous extract of the star fruit. The effects of the neurotoxic fraction AcTx given to experimental animals (rats and mice) showed behavioural changes acting primarily on g-aminobutyric acid (GABA) receptors.[12] These excitatory neurotoxins, probably GABAergic antagonists, may be responsible for seizures in renal patients and animal models.[13]   

In another experiment, an aqueous extract of the Averrhoa carambola leaves is shown to induce some electrophysiological changes in a normal guinea pig heart. In 6 hearts, the extract induced many kinds of atrioventricular blocks (1st, 2nd, and 3rd degrees); increased the QT interval; increased the QRS complex duration, and depressed the cardiac rate.[14]

Clinical Data

Clinical Trials

No documentation

Adverse Effects in Human:

Neurotoxic effect 

A preliminary report on intoxication by Averrhoa carambola fruit observed six cases of patients in a dialysis programme who were apparently intoxicated after ingestion of 2-3 fruits or an equivalent of 150-200 ml of the fruit juice. The six patients who had previously been stable, however developed a variety of symptoms ranging from insomnia and hiccups to agitation, mental confusion and one case of death.[11] In a similar situation, neurologic symptoms following star fruit ingestion were exhibited by 32 uraemic patients. All patients who were promptly and properly treated with haemodialysis recovered without sequelae. Patients with severe intoxication who were not treated or treated with peritoneal dialysis did not survive.[15] It appears that star fruit contains an excitatory neurotoxin and as a precaution, patients with renal failure should avoid consuming it.[11]

Use in Certain Conditions

Pregnancy / Breastfeeding

No documentation

Age Limitations

Neonates / Adolescents

No documentation


No documentation

Chronic Disease Conditions

No documentation


Interactions with drugs

The chemical component(s) in filtered star fruit juice has shown potent inhibitory effect on midazolam 1’-hydroxylase activity of human CYP3A activity.[16]

Interactions with Other Herbs / Herbal Constituents

No documentation



In acute inflammation of the urinary tract as the star fruit juice contains oxalates.[17]

Case Reports


A 25-year-old female had been enrolled in a regular haemodialysis programme for 6 years. She ate one star fruit and developed hiccups 2 h later. Four hours later she ate four more fruits and showed intractable hiccups half hour later, followed by vomiting. The patient went to the University Hospital and the hiccups disappeared after a total of 14 h of dialysis in 4 days. The patient had no sequelae. There had been no laboratory tests during these 7 days of follow-up.[15]

A 55-year-old female who enrolled in a regular CAPD programme had been on dialysis for 27 months. She ingested a star fruit and developed hiccups, vomiting, asthenia and mild psychomotor agitation 3 h later. At the emergency room, she was medicated with chlorpromazine and metoclopramide and was discharged. Seven and a half hours after star fruit ingestion, she presented with mental confusion and was admitted to the hospital. She was admitted to an ICU with moderate mental confusion and, 12 h after fruit ingestion, presented with convulsive activity. She was seen by a neurologist who prescribed hydantoin 400 mg i.v., phenobarbital and diazepam. The convulsive activities progressed to status epilepticus. At 22 h after fruit ingestion, she showed haemodynamic instability with low blood pressure, and was given dopamine. She was continued on dialytic treatment (CAPD, now increased to every 4 h) and was given haemodialysis 22 h after fruit ingestion, but died 2 h later during this procedure.[15]


  1. Herbal Medicine Research Centre, Institute for Medical Research, Kuala Lumpur. Compendium of Medicinal Plants Used in Malaysia. 2002; 1:92.
  2. National Tropical Botanical Garden Plant Database. http://www.ntbg.org. Accessed on 19 May 2007
  3. Philippine Medicinal Plants, http://www.stuartxchange.org/Balimbing.html. Accessed on 19 May 2007
  4. Dr Duke’s Phytochemical and Ethnobotanical Databases http://sun.ars- gin.gov:8080/npgspub/xsql/duke/plantdisp.xsql?taxo . Accessed on 15 May 2007
  5. Kamarudin Mat-Salleh, A Latiff eds. Tumbuhan Ubatan Malaysia. UKM, Bangi. 2002.
  6. Sripanidkulchai B. et al. Anti-inflammatory and Bactericidal Properties of Selected Indigenous Medicinal Plants Used for Dysuria. Thai J. Pharm.Sci. 2002 ; 26 : 34-38
  7. Chau C.F. et al. Insoluble fiber-rich fractions derived from Averrhoa carambola : hypoglycaemic effects determined by in vitro methods. Lebensm.-Wiss. u Technol.2004 ; 37: 331-335.
  8. Shui G, Leong L.P. Analysis of polyphenolic antioxidants in star fruit using liquid chromatography and mass spectrometry. J Chromatogr A. 2004 ; 1022 (1-2) :67-75
  9. Shui G, Leong L.P. Residue from star fruit as valuable source for functional food ingredients and antioxidant nutraceuticals. Food Chemistry 2006 ; 97 : 277-284
  10. Chau C.F. et al. Effects of a novel pomace fibre on lipid and cholesterol metabolism in the hamster. Nutrition Research 2004 ; 24: 337-345
  11. Neto,M. M. et al. Intoxication by star fruit (Averrhoa carambola) in six dialysis patients ? (Preliminary report). Nephrol Dial Transplant. 1998 ;  13: 570-572.
  12. Carolino R.O.G. et al. Convulsant activity and neurochemical alterations induced by a fraction obtained from fruit Averrhoa carambola (Oxalidaceae: Geraniales), Neurochem Int. 2005; 46:523-531
  13. Rodrigues M.C.A. et al. Correlation between shaking behaviors and seizure severity in five animal models of convulsive seizures. Epilepsy & Behavior 2005; 6: 328-336
  14. Vasconcelos C.M. et al. Electrophysiological effects of the aqueous extract of Averrhoa carambola L. leaves on the guinea pig heart. Phytomedicine. 2006; 13(7):501-508 
  15. Neto,M. M. et al. Intoxication by star fruit (Averrhoa carambola) in 32 uraemic patients : treatment and outcome. Nephrol Dial Transplant 2003 ; 18: 120-125.
  16. Hidaka M, et al.. Potent inhibition by star fruit of human cytochrome P450 3A (CYP3A) activity. Drug Metab. Dispos. 2004; 32(6):581-583
  17. Brinker, F. 2007. Online updates and additions to “Herb contraindications and drug interactions”, 3rd ed. http://www.eclecticherb.com/emp/updatesHCDI.html. Accessed on 26 Sept 2007.