Description: MPTP is a contaminant that can result from sloppy synthesis of MPPP, a street analog of the opioid meperidine (Demerol). It is a known industrial toxin that was responsible for a rash of Parkinsons-like cases in the early 1980s which spurred the development of the federal Analogue Act in the U.S. (1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine)