Used in neuroscience and histology to stain neural tissue sections, allowing clear visualization of cell bodies and neuronal structures. The stain selectively colors Nissl substances—aggregates of rough endoplasmic reticulum and ribosomes—dark violet, helping distinguish neurons from surrounding tissue. Commonly applied in brain and spinal cord studies to assess neuronal damage, degeneration, or distribution in research on neurodegenerative diseases, brain mapping, and neurodevelopment. The method is compatible with paraffin-embedded and frozen sections, making it a standard in both diagnostic and research laboratories.