Saffron O is a cationic dye that binds multiple anions, basophilic cartilage combines with the basic dye Saffron O to show red color, it is often used in combination with solid green to show cartilage, which is based on the binding of anionic groups in the cationic dye mucopolysaccharides, and acidophilic bone combines with the acidic dye solid green to show green or blue color, which contrasts sharply with the cartilage showing red color to distinguish cartilage tissues from bone tissues, and it can also be used for It can also be used for the staining of mast cells, etc. Saffron O ethanol solution is also known as Saffron wine solution.