Cochineal, a red or purple dye obtained from the female of a small scale insect. The dye was formerly used as a food coloring and for this purpose has been largely replaced by synthetic dyes. It is still a source of carmine and is still used as a dye in cosmetics, medicines, and biological laboratory staining fluids.

Cochineal insects feed principally on a branching, almost treelike, kind of cactus. Plantations of these cacti were established for the insects in Mexico, Peru, Spain, Algeria, and Java. The reddish-brown insect is covered with a white, mealy powder, and is the size of a small split pea. Cochineal dye is produced by soaking the dried insects in water.

The cochineal insect is Dactylopius coccus of the family Dactylopiidae. The cochineal cactus is Nopalea cochenillifera of the family Cactaceae. The chemical formula for carminic acid is C22H20O13.