Carmine red, alternately known as Cochineal, Crimson Lake, and Natural Red 4, was a favorite of the Aztecs and is perhaps the oldest true red dye. It's no less popular today than it was in the court of Moctezuma I, and is used in everything from Cherry Coke to your favorite lip glosses and eye shadows. There's just one little catch: carmine is made from the boiled, dried, then powdered bodies of female cochineal beetles. This is problematic for vegetarians and people who oppose the use of animal products in cosmetics. So this January, the FDA passed a new regulation requiring that cochineal and carmine be listed by name on labels. It doesn't go into effect 'til Jan. 5, 2011, though, so you've got a while to wait for the info on whether your favorite products are full of creepy crawlies.
Photo by Flickr User madame_furie