Indigo carmine is widely used as a dye in various medical and industrial applications. In the medical field, it serves as a diagnostic agent during surgical procedures, particularly in urology and gynecology, to identify and locate specific structures or abnormalities. For example, it is commonly used in cystoscopy to visualize the urinary tract and detect issues like leaks or blockages. Additionally, it is employed as a pH indicator in certain diagnostic tests due to its color-changing properties in response to acidity or alkalinity. In industrial settings, indigo carmine is utilized as a dye in textiles, food, and cosmetics, providing a vibrant blue color. It is also used in microbiology as a staining agent to enhance the visibility of microorganisms under a microscope. Despite its versatile applications, its use is carefully regulated due to potential allergic reactions or adverse effects in some individuals.