Ethidium bromide is a typical nucleic acid stain used by molecular biologists. Dark red and in crystal form when not in an aqueous solution, the fluorochrome exhibits a reddish-orange fluorescence that can be detected under both long and short ultraviolet wavelengths of light. Furthermore, ethidium bromide is a relatively large, flat basic molecule that somewhat resembles a DNA base pair and because of its structure can easily insert into a DNA strand. Thus, the substance is extremely useful for experimental purposes, though it can dangerous to handle and should be employed with caution.