Red powder is a term with multiple meanings. Here are two interpretations: Firstly, red powder is a widely used ammonia aniline dye, also known as 221 purple 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 powder has a broad range of applications and is an important pigment in many industries. Secondly, red powder can also refer to Rhodamine B, which is a bright pink synthetic basic fluorescent dye, also known as rose red B or basic rose essence. Rhodamine B is mainly used as a cell fluorescent stain in laboratories, dyeing agents, 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 suspected.