Borax carmine is a staining method in histology that uses borax (sodium borate) and carmine (a red dye extracted from cochineal lice). The borax-carmine solution is used to stain cell structures such as nuclei and cytoplasm in tissue sections red. This staining is particularly useful for examining chromosomes and cell structures in microscopy. Borax carmine staining allows good contrasting of cell structures and thus facilitates histological analysis and diagnosis of cellular changes.