Red Madder has multiple meanings. Here are two definitions for you: Firstly, Red Madder is a widely-used azo dye, also known as 221 Violet Red Powder. It is primarily used for coloring paints, inks, varnishes, leather, rubber, plastics, latex products, construction materials, printing inks, educational supplies, and cosmetics. Red Madder has a broad range of applications and is an important pigment in many industries. Secondly, Red Madder can also refer to Rhodamine B, which is a bright peach-red synthetic basic fluorescent dye, also known as Rose Red B or Basic Rose. Rhodamine B is mainly used in laboratory cell fluorescence stains, dyes, papermaking, manufacturing paints and pigments, and can also be used for dyeing fabrics and leather products. However, Rhodamine B has certain toxicity and genotoxicity, and international research institutions classify it as a Class 3 carcinogen, meaning its carcinogenicity to humans is questionable.