Red powder has multiple meanings, and here are two definitions: Firstly, red powder is a widely used aniline red pigment, also known as 221 purple red powder. It is primarily used for coloring coatings, inks, paints, leather, rubber, plastics, latex products, building materials, printing inks, educational and cultural products, and cosmetics. Red powder has a broad range of applications and is an important pigment in many industries. Secondly, red powder can also refer to Rhodamine B, a bright peach red synthetic basic fluorescent dye, also known as rose red B or basic rose essence. Rhodamine B is mainly used in laboratory cell fluorescence stains, dyes, papermaking industry, 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 have listed it as a Class 3 carcinogen, meaning its carcinogenicity to humans is questionable.