Used primarily in histology to differentiate tissue components under the microscope. It stains collagen fibers blue or green depending on the formulation, cytoplasm red or pink, and muscle fibers red with distinct clarity. This contrast makes it valuable in assessing fibrosis in tissues such as liver, heart, and kidney. Commonly applied in research and diagnostic pathology to evaluate connective tissue disorders, tumor stroma, and muscle damage. The stain is especially useful in distinguishing between old and new collagen deposition, aiding in the study of wound healing and chronic inflammatory conditions.