Cocaine is the powdered form of a very powerful stimulant drug. Its freebase version - which is more dangerous as it has not been chemically neutralised with an acid base - is called crack cocaine or just crack. Typically the powder is snorted up through the nose or mixed with water and injected. Other common names for cocaine include coke, blow, snow, candy and charlie. Cocaine produces an immediate and very potent pleasurable "high" effect. Desiring to repeat the pleasant experience causes first a psychological and later a physical addiction in users. Many cocaine addicts develop a tolerance over time which means they need to take bigger hits more frequently to achieve the same effects.