Indigo Carmine: Between Necessity and Concern

Dyes, as indigo carmine have become indispensable to modern life being widely used in food, textile, pharmaceutical, medicine and cosmetic industries. Although indigo carmine is considered toxic and presents many adverse effects, it is heavily used in the food industry because the blue pigment is difficult to obtain from natural sources and is one of the most used dyes in the textile industry, especially for dyeing denim. Also, indigo carmine is one of the dyes used in medicine as diagnostic agent because it has impressive applicability in terms of diagnostic methods and surgical procedures. In the literature it is reported that indigo carmine is toxic for humans and can cause various pathologies, such as hypertension, hypotension, skin irritations, corneal and conjunctival disorders or gastrointestinal disorders. In this review, we discuss the structure and properties of indigo carmine, its use in various industries and medicine, the adverse effects of its ingestion, injection or skin contact, the effects on environmental pollution and its toxicity testing.