The cashew (Anacardium occidentale; syn. Anacardium curatellifolium A.St.-Hil.) is a tree in the flowering plant family Anacardiaceae. The plant is native to northeastern Brazil. Its English name derives from the Portuguese name for the fruit of the cashew tree, caju, which in turn derives from the indigenous Tupi name, acajú. It is now widely grown in tropical climates for its cashew "nuts" (see below) and cashew apples.

What appears to be the fruit of the cashew tree is an oval or pear-shaped accessory fruit or false fruit that develops from the receptacle of the cashew flower. Called the cashew apple, better known in Central America as "jocote de marañón", it ripens into a yellow and/or red structure about 5–11 cm long. It is edible, and has a strong "sweet" smell and a sweet taste. The pulp of the cashew apple is very juicy, but the skin is fragile, making it unsuitable for transport. It is often used as a flavor in agua fresca.

The true fruit of the cashew tree is a kidney or boxing-glove shaped drupe that grows at the end of the pseudofruit. The drupe develops first on the tree, and then the peduncle expands into the pseudofruit. Within the true fruit is a single seed, the cashew nut. Although a nut in the culinary sense, in the botanical sense the fruit of the cashew is a seed. The seed is surrounded by a double shell containing a dermatogenic phenolic resin, urushiol, a potent skin irritant toxin also found in the related poison ivy. Some people are allergic to cashew nuts, but cashews are a less frequent allergen than nuts or peanuts .

Cashew industry and production

One cashew tree produces between 200 and 300 cashew nuts in a year.

The world's total area under the cultivation of cashew is around 33,900 km². India ranks first in area utilized for cashew production, though its yields are relatively low. The world's average yield is 817 pounds per acre (916 kg/hectare) of land.

Collectively, Vietnam, Nigeria, India and Brazil account for more than 90% of all cashew kernel exports.

Uses

Medicine and industry

main: Cashew nutshell liquid The cashew nutshell liquid (CNSL), a by-product of processing cashew, is mostly composed of anacardic acids. These acids have been used effectively against tooth abscesses due to their lethality to gram-positive bacteria. They are also active against a wide range of other gram-positive bacteria. Many parts of the plant are used by the Patamona of Guyana medicinally. The bark is scraped and soaked overnight or boiled as an antidiarrheal. Seeds are ground up into powders used for antivenom for snake bites. The nut oil is used topically as an antifungal and for healing cracked heels.