Live/dead viability staining describes a number of potential dyes where one specifically stains live cells (usually resulting in green fluorescence) while the other dye stains dead cells (usually with red fluorescence). An example would be calcein AM with ethidium homodimer-1 but there are many combinations which generally involve a membrane-permeable dye which is metabolized within viable cells, mixed with a membrane-impermeable DNA binding molecule. The calcein AM is membrane permeable and is cleaved by esterases in live cells to yield cytoplasmic green fluorescence. The membrane-impermeable ethidium homodimer-1 labels nucleic acids of membrane-compromised cells (i.e. dead) with red fluorescence. The ratio of live to dead then can easily be determined by simple counting. In assays such as live/dead staining, there is also the possibility to include macro-based analysis within the workflow. A carefully written macro in combination with image analysis can provide rapid quantification of hundreds of images and yet this method is currently underutilised by many laboratories.