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 Mucopolysaccharide, 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, thus differentiating the cartilage tissues from the bone tissues, and it can also be used to stain plant specimens. It can also be used for staining plant specimens and mast cells.