The cashew apple is a fruit, whose pulp can be processed into a sweet fruit drink or distilled into liquor.
The shell of the cashew seed yields derivatives that can be used in many applications from lubricants to paints, and other parts of the tree have traditionally been used for snake-bites and other folk remedies.
The true fruit of the Cashew tree is the drupe that grows at the end of the Cashew apple, within this drupe is a single seed which is the Cashew nut.
In their raw form, the outer layer of the fruit contains multiple toxins—including anacardic acid, a powerful skin irritant similar to the toxin found in poison ivy. Roasting the cashews destroys the toxins, but roasting must be performed carefully outdoors because the smoke can irritate the lungs. When they are roasted, cashews change from their natural greenish-grey color to the light brown ‘nut’ sold in stores.
This is why Cashew nuts are not sold in their shells to consumers.