IncuCyte® Cytotox Reagents are highly sensitive cyanine nucleic acid dyes ideally suited to a simple mix-and-read, real-time quantification of cell death. Addition of the IncuCyte Cytotox Reagents to normal healthy cells is non-perturbing to cell growth or morphology and yields little or no intrinsic fluorescent signal. Once cells become unhealthy plasma membrane integrity diminishes, allowing entry of the IncuCyte Cytotox Reagent and yielding a 100-1000-fold increase in fluorescence upon binding to deoxyribonucleic acid (DNA). With the IncuCyte® integrated analysis software fluorescent objects can be quantified and background fluorescence minimized.