Erythrosin B solution is widely used as a biological stain in microscopy to enhance the visibility of cellular structures. It is particularly effective in staining living cells for viability assays, helping to differentiate between live and dead cells. In the food industry, it serves as a colorant, imparting a bright red hue to products like candies, baked goods, and canned fruits. Additionally, it is employed in dental plaque disclosure tablets to highlight areas of plaque buildup on teeth, aiding in oral hygiene practices. In research, it is utilized as a photosensitizer in photodynamic therapy studies due to its ability to generate reactive oxygen species upon light exposure.