Spectrum Chemical manufactures and distributes fine chemicals with quality you can count on including those with CAS number 51481-61-9, Whether you call it Cimetidine, Tagamet or 2-Cyano-1-methyl-3-[2-(5-methylimidazol-4-ylmethylthio)ethyl]guanidine you can be assured the Cimetidine products offered by Spectrum, meet or exceed the grade requirements or specifications for each individual product.