7-Aminoactinomycin D (7-AAD) is a red fluorescent chemical compound with a strong affinity for DNA. This live-cell impermeant vital dye intercalates in double-stranded DNA with a high affinity for GC-rich regions. 7-AAD does not pass through intact cell membranes, allowing it to be used as a cell viability dye. Alternatively, it may also be used to visualize or label all cells after fixation.