The great amount of METH abuse all over the world causes enormous social and criminal justice problems. In the human brain the abuse of METH causes implications on both structures and functions given rise to acute as well as long term symptoms. In this essay the effects of METH abuse is described in the manner of the drug mechanism such as the impact on neurotransmitters, structural deficits with decreased and increased volumes and the implication on attention, memory, decision making and emotions. Results from studies showing brain structural and cognitive impairments in METH abusers and in prenatal METH exposed children.