A number of cultivars have been developed in recent years.
The most common cultivars grown commercially include the sweet types "Arkin" (Florida), "Dah Pon" (Taiwan), "Ma fueng" (Thailand), "Maha" (Malaysia), and "Demak" (Indonesia) and the sour types "Golden Star", "Newcomb", "Star King", and "Thayer" (all from Florida).
Scavenging of nitric oxide (NO) by the fruit extract is dependent on concentration and stage of ripening. coli, Klebsiella spp., Staphylococcus aureus, and Pseudomonas aeruginosa. Both substances are harmful to individuals suffering from kidney failure, kidney stones, or those under kidney dialysis treatment.
Consumption by those with kidney failure can produce hiccups, vomiting, nausea, mental confusion, and sometimes death.
Overripe carambola will be yellow with brown spots and can become blander in taste and soggier in consistency.
The tree is also cultivated throughout non-indigenous tropical areas.
The fruit has distinctive ridges running down its sides (usually five but can sometimes vary); when cut in cross-section, it resembles a star, hence its name.
They are also grown in Nicaragua, Guatemala, Guyana, Panama, Colombia, Ecuador, El Salvador, Peru, Brazil, Jamaica, Haiti, the Dominican Republic, Puerto Rico, Trinidad, Mexico, Costa Rica and parts of Africa.
The fruit is about 5 to 15 centimetres (2 to 6 inches) in length and is an oval shape.