Neutral Red is widely used as a biological stain in microscopy to highlight living cells in tissues. It is particularly effective in staining lysosomes and other acidic organelles due to its ability to permeate cell membranes and accumulate in these compartments. In cell viability assays, Neutral Red is employed to assess cell health and membrane integrity, as living cells uptake the dye while dead or damaged cells do not. Additionally, it serves as a pH indicator, changing color in response to varying acidity levels, making it useful in pH monitoring experiments. In environmental studies, Neutral Red is utilized to evaluate the cytotoxicity of pollutants, providing insights into their potential harm to aquatic organisms. Its applications extend to histology, where it aids in differentiating cell types and structures under microscopic examination.