Methamphetamine (Meth) is a synthetic stimulant that affects the central nervous system. It is one of the most addictive drugs in the world. Meth is a dangerous drug that first acts as a stimulant but then begins to systematically destroy the body. It can cause serious health conditions, including memory loss, aggression, psychotic behavior and potential heart and brain damage. The other name for meth are crystal meth, ice, glass, chalk, crank, fire etc.