Quantification of the number of viable cells is an indispensable tool in cell biology research. MTT Cell Proliferation Assay Kit is a sensitive method for quantification of viable cells in proliferation and cytotoxicity assay. The method is based on the conversion of water soluble MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) compound to an insoluble formazan product. Viable cells with active metabolism convert MTT into formazan, however, dead cells lose this ability. Thus color formation serves as a useful and convenient marker of only the viable cells. The measured absorbance (590 nm) is proportional to the number of viable cells. This assay kit provides an easy-to-use, non-radioactive, and high-throughput method for cell proliferation, cell viability, chemotaxis, cytotoxicity, and apoptosis.