Eosin B is widely used as a biological stain in histology and cytology to highlight cellular structures under a microscope. It is particularly effective in staining cytoplasm, collagen, and muscle fibers, often paired with hematoxylin in the H&E staining method for tissue samples. In the textile industry, it serves as a dye for fabrics, providing vibrant red or pink shades. Additionally, Eosin B is employed in the paper industry to color paper products. It also finds use in forensic science as a marker for detecting latent fingerprints on porous surfaces. In microbiology, it aids in differentiating bacterial colonies in certain culture media. Its fluorescent properties make it useful in fluorescence microscopy for visualizing specific biological components.