Crack cocaine (or just crack) is an illegal drug which is made from cocaine. Cocaine is mostly an illegal drug that comes from the leaves of a plant called coca. When people smoke crack, they have a feeling called "being high." The name "crack" comes from the cracking sound the drug makes as it is smoked. The cracking sound is caused by evaporating water escaping. In most parts of the world, production (making crack), possession (having crack), and distribution (selling or giving away crack) are illegal.