What does acridine orange stain?

Acridine orange is a dye that binds with nucleic acids (DNA or RNA) to emit different colors. The dye stains DNA a yellow-green color, and stains RNA a bright red color. It also stains bacteria and fungi bright orange. Additionally, it stains human epithelial and inflammatory cells pale green to yellow. This is a useful dye for cell-cycle studies, for detecting DNA and RNA in brain tissue, and has been also used as a lysosomal dye.