GelGreen is an intercalating nucleic acid stain used in molecular genetics for agarose gel DNA electrophoresis.

GelGreen consists of two acridine orange subunits that are bridged by a linear oxygenated spacer.

[1][2] Its fluorophore, and therefore its optical properties, are essentially identical to those of other N-alkylacridinium orange dyes.

When exposed to ultraviolet light, it will fluoresce with a greenish color that strongly intensifies after binding to DNA.

[3] The substance is marketed as a less toxic and more sensitive alternative to ethidium bromide.