Used primarily in histology and microbiology for staining tissue sections and microorganisms. It helps differentiate acid-fast bacteria, such as Mycobacterium species, from non-acid-fast bacteria under the microscope. The stain is especially useful in diagnosing tuberculosis and leprosy by highlighting the waxy cell walls of acid-fast organisms. It is often used in conjunction with other stains in a multi-step procedure to improve contrast and cellular detail. Commonly applied in clinical laboratories for smear testing of sputum, tissue samples, and other clinical specimens.