Red No. 40 is a chemical known as Allura Red AC (E129 in Europe) that is often used in products, such as chewing gum and frosting, to help dissolve the dye and prevent the colors from bleeding.

Dyes tend to be listed toward the end. Red dye 40 may be listed as a couple of names, including Red 40, Allura Red, Red 40 Lake, INS No. 129 and E129. It can also be found in some cosmetics and ...