Crystal meth is a powerful, highly addictive stimulant that affects the central nervous system. Also known as meth, chalk, ice, and crystal, it takes the form of a white, odorless, bitter-tasting crystalline powder that dissolves readily in water or alcohol. Developed in the early 20th century from its predecessor, amphetamine, it was originally used in nasal sprays and bronchial inhalers. Like amphetamine, methamphetamine causes increased activity and talkativeness, decreased appetite, and a pleasant feeling of well-being or euphoria. However, methamphetamine differs from amphetamine in that, at comparable doses, much larger amounts of the drug reach the brain, making it a more potent stimulant. It also has longer-lasting and more damaging effects on the central nervous system. These properties make it a drug with a high potential for abuse.