Ext. D&C Average Colouring Agent/Pigment No known benefits Ext. D&C description Type of colouring agent. According to the FDA’s website (www.fda.gov), when” Ext. D&C” is followed by a colour, it means that the colour is certified as safe for use only in drugs and cosmetics meant for external use, but not around the eyes or mouth. These types of colouring agents is not safe for foods.