The newly-released Peeps Oreos have quickly become a source of amusement - after customers claimed the pink marshmallow-flavored creme turned their poop pink.
But studies show there could be a more sinister side to the food coloring behind the funny side effect.
According to Oreo's list of ingredients, the bright pink creme is colored with FD&C Red No 3 - a source of controversy that dates back almost 50 years.
Health experts have long been petitioning the FDA to ban the product class from food, since several studies linked it to breast cancer, thyroid tumors and hyperactivism in young children.
In 1990, the FDA banned the dye from cosmetics and external drugs use.
However, it remains commonplace is commercial food products because the agency claims regular safety reviews have shown no health dangers.
The newly-released Peeps Oreo with a pink marshmallow-flavored creme has reportedly turned people's saliva and stool bright pink, but there are claims it could be far more damaging to your health - with some studies linking the dye to cancer
Controversy over the dye resurfaced two weeks ago, when Peeps Oreo hit the market.
Peeps are marshmallow candies, sold in the US and Canada, that are shaped into chicks, bunnies, and other animals. They are particularly popular around Easter.
The world became captivated by the pink dye when several accounts on social media told of stool turning pink after eating a whole pack of Peeps Oreo, with many saying their tongues and saliva remained pink for at least 24 hours.
This is because the food dye used to make these Oreos isn't broken down in the body during digestion, Dr Ian Lustbader, a gastroenterologist at New York University's Langone Medical Center, told Live Science.
In most foods, the compounds are chemically broken down as they make their way through the digestive system. However, depending on the molecules, some things may not be 'amenable' to being broken down, Dr Lustbader said.
When Oreos pass through the digestive system, the coloring is usually turned into a lighter color, and mixed in with stomach fluid and other liquids in the digestive tract.
By the time you make a bowel movement, you don't see any unusual color.
With the Peeps Oreos, however, once the pink coloring reaches the colon, the excess water is removed and reabsorbed by the body.
Dr Lustbader explained that the color then becomes more concentrated, turning from a lighter pink to a darker pink.
The gastroenterologist was quick to add that eating a cookie or two will not turn your poop pink.
Although approved by the FDA, the coloring has been linked to cancers and thyroid tumors in young children. It was banned from cosmetic use in 1990 but is still used in food products
Fifteen million pounds of food dyes are sold every year in the US to make typically unattractive ingredient mixtures more aesthetically pleasing to consumers.
Due to cancer concerns, Red dyes No 1, No 2 and No 4 were banned, but No 3 continues to be widely used today.
In 2008, the Center for Science in the Public Interest petitioned the FDA for a complete ban on No 3, along with several other dyes to no avail.
This is despite the FDA recognizing the coloring as a thyroid carcinogen.
Daily Mail Online has contacted Nabisco, the makers of Oreo products, for comment.
WHAT IS FD&C Red No 3 DYE?
The dye stands for Food, Drug & Cosmetic Colors Red No 3, and is also known as erythrosine.
It can be found in:
- Canned fruit
- Ice cream
- Maraschino cherries
- Gelatin desserts
- Sausage casings
- Cake icings
In 1990, the FDA instituted a partial ban on the dye, in cosmetics and external drugs, after it had found to cause cancer in laboratory rats.
The dye has also been linked to cases of breast cancer, in a study from the Certified Color Manufacturers' Association.
Other studies found it caused thyroid tumors and hyperactivity in children.
Despite the FDA recognizing the drug as a thyroid carcinogen, the agency claims that color additives undergo safety reviews prior to approval for marketing and that the safety concerns are unsubstantiated.