Erythrosin B is widely used as a red dye in the food industry, particularly in coloring candies, baked goods, and canned fruits. It is also employed in cosmetics, such as lipsticks and blushes, to provide a vibrant red hue. In the medical field, it serves as a diagnostic tool in ophthalmology for detecting corneal abrasions and in dental plaque disclosure. Additionally, it is utilized in microbiology as a stain to differentiate between bacterial colonies. Its photochemical properties make it useful in light-sensitive materials and as a sensitizer in photovoltaic cells.