Evan's blue is widely used in biomedical research as a vital dye for assessing blood-brain barrier integrity. It binds to serum albumin, allowing researchers to track and visualize vascular permeability and leakage in experimental models. The dye is also employed in studies of plasma volume measurement, as it distributes within the vascular compartment and can be quantified spectrophotometrically. Additionally, Evan's blue is utilized in cell viability assays, where it helps differentiate between live and dead cells based on membrane integrity. Its application extends to histology, where it serves as a staining agent to highlight tissue structures and abnormalities. In pharmacology, it aids in evaluating drug delivery systems by monitoring the distribution and efficacy of therapeutic agents. It is also used to assess kidney function by measuring its excretion in urine to evaluate renal filtration efficiency. Overall, Evan's blue is a versatile tool in both diagnostic and experimental settings.