FD&C RED 40, Allura Red AC

Allura Red AC is a water soluble red azo dye that goes by several names, including FD&C Red 40. It is used as a food dye and has the E number E129.
In solution, its maximum absorbance lies at about 504 nm (Absorbs green color).
In the United States, Allura Red AC is approved by the FDA for use in cosmetics, drugs, and food. It is used in some tattoo inks and is used in many products, such as cotton candy, soft drinks, cherry-flavored products, children’s medications, and dairy products. It is occasionally used to dye medicinal pills, such as the antihistamine fexofenadine, for purely aesthetic reasons. FDC RED 40 is by far the most commonly used red dye in the United States,[8] completely replacing amaranth (Red 2) and also replacing erythrosine (Red 3) in most applications due to the negative health effects of those two dyes.