Sudan Black B is widely used as a biological stain in histology and cytology to detect lipids, lipoproteins, and other fat-containing structures in tissues and cells. It is particularly valuable in identifying myelinated nerve fibers and lipid-rich structures in bone marrow smears, making it a critical tool in diagnosing hematological disorders. In microbiology, it is employed to stain lipid granules in bacteria, aiding in the study of microbial metabolism. Additionally, Sudan Black B is utilized in industrial applications for dyeing plastics, oils, and waxes due to its strong affinity for hydrophobic materials. Its ability to bind selectively to lipids makes it a versatile reagent in both biological research and material science.