Ponceau 4R is a brilliant-red dye that is also known as E124, C. I. 16255, SX Purple, New Coccine Cochineal Red A, and Brilliant Scarlet 4R. It was introduced into manufacturing as a substitute for a red dye that used to be made from cochineal bugs, although there are no actual insects used to make Ponceau 4R today. There is also a Ponceau 2R that is used to stain tissue samples for examination under the microscope, and a Ponceau 6R with similar chemical properties that is used as a red dye in a smaller number of foodstuffs.
What kinds of foods and beverages are colored with Ponceau 4R? It's used to add a red tint to cherry strawberry juice. It's also used to color dessert toppings, salami, fruit pie fillings, cake mixes, soups, truffles (the candy variety), and trifles.
What's the problem with Ponceau 4R? All of the Ponceau red dyes are chemically related to Allura red (E129), carmoisine (E122), sodium benzoate (E211), Sunset Yellow (E110), and tartrazine (E102). The differences among the dyes are in how reactive they are at room temperature. All of the dyes in this class are partially cross-reactive with aspirin. That means that if you have an allergy to aspirin, you will also have an allergy to the dye, and taking and aspirin and consuming a food or beverage that contains the dye will have additive effects. The dye can make an aspirin allergy worse and aspirin can make the dye allergy worse.
Only about 1 in 300 people will have an allergic reaction, usually a skin reaction, after exposure to Ponceau 4R. About 1 in 1200 people will have an autoimmune reaction to repeated exposure to Ponceau 4R. Allergic reactions triggered by this dye are usually similar to hives, but not as severe. Autoimmune reactions caused by long-term exposure to this dye seem to be related to migraines in adults and attention deficit hyperactivity disorder in children and teens, although exposure to Ponceau 4R is always only one of many factors contributing to these conditions.
There's about a 99% probability that exposure to Ponceau 4R won't cause you any harm. If you happen to be in that other 1%, however, Ponceau 4R can go a long way toward making your life miserable. The best way to avoid the problem is to make your own cherry and strawberry juices with an extraction juicer. They will taste a lot better and you won't need dyes to make them look delicious.