Auramine O is widely used as a fluorescent dye in various biological and industrial applications. In microbiology, it serves as a vital staining agent for the detection of acid-fast bacteria, such as Mycobacterium tuberculosis, in sputum samples. The dye binds to the mycolic acid in the bacterial cell walls, making them visible under a fluorescence microscope. Additionally, it is employed in histology for staining tissues to highlight specific structures, aiding in diagnostic and research studies. In the textile industry, Auramine O is utilized for dyeing materials like paper, leather, and silk, providing vibrant yellow hues. Its fluorescent properties also make it useful in certain analytical chemistry techniques, such as tracing and labeling in experimental procedures. However, due to its potential toxicity and carcinogenic nature, its use is carefully regulated, and safer alternatives are often sought.