Ethidium bromide is a dark red, fluorescent, non-radioactive, intercalating dye widely used for staining DNA in agarose gels. It is also excited by ultraviolet light and has UV absorbance maxima at 300 and 360 nm and an emission maximum at 590 nm.

Ethidium bromide fluoresces a red-orange color under UV light and with increased 20 -25 increased brightness when bound to double-stranded DNA.