In 1971, Walt Disney World had just opened in Orlando, Florida. Led Zepplin was about to blow our minds, a prison riot had been shut down at Attica, and all across America, kids were pooping pink. Hundreds of mothers hospitalized their children for fecal testing out of fear of internal bleeding. Within that same year, not-so-coincidentally, General Mills released their classic monster cereals Count Chocula and Franken Berry. The latter was colored red using “Food, Drug and Cosmetics” (FD & C) Red No. 2 and No. 3., originally and chemically known as amaranth, a synthetic color named after the natural flower. The synthetic dye can’t be broken down or absorbed by the body.

A 1972 case study, “Benign Red Pigmentation of Stool Resulting from Food Coloring in a New Breakfast Cereal (The Franken Berry Stool),” published in Pediatrics explains the phenomenon later known as “Franken Berry Stool.” A 12-year-old boy was hospitalized for four days after being admitted for possible rectal bleeding. “The stool had no abnormal odor but looked like strawberry ice cream,” Payne reports. Further questioning of the mother revealed that the child had enjoyed a bowl of Franken Berry cereal two days and one day prior to his hospitalization. By the fourth day, they did a little experiment: They fed the boy four bowls of Franken Berry cereal and for the next two days, he passed bright pink stools. But other than pink poop, there were no other symptoms, Payne reports, “Physical examination upon admission revealed in no acute distress and with normal vital signs…Physical examination was otherwise unremarkable.”

At the time of the study, the product had only been on the market for a few weeks. The author warns that “physicians should be aware of its potential for producing reddish stools.” Other monster cereals at the time also used dyes that caused stool to change colors. Booberry, which debuted in December of 1972, for example, uses Blue No. 1 (a dye currently banned in Norway, Finland and France) and turns stool green. Apparently, green stool seems less life-threatening than the reddish hue caused by Franken Berry.

But pink poop wasn’t always the worst side effect from colored confections. Ruth Winters’s A Consumer’s Dictionary of Cosmetic Ingredients details the history of commercial food dyes, including those later used in Franken Berry. At the turn of the 20th century, with virtually no regulation of more than 80 dyes used to color food, the same dyes used for clothes could also be used to color confections and other edibles.

In 1906, Congress passed the first legislation for food colors, the Pure Food and Drug Act, deeming seven colors suitable for use in food: orange, erythrosine, ponceu 3R, amaranth (the color later used in Franken Berry cereal), indigotin, naphthol yellow, and light green. Since then, upon further study, several of these choices have been delisted.

More than 20 years later, in 1938, Congress passed the Federal Food, Drug, and Cosmetic Act which gave these colors numbers instead of chemical names—every batch needed to be certified by the Food and Drug Administration, though some problems still arose: in the fall of 1950, many children became ill from eating an orange Halloween candy containing one to two percent FD&C Orange No. 1, for example.

Red Dye No. 2, the one used by the original Franken Berry cereal, was one of the most widely used color additives at the time, until a 1971 Russian study reported that the dyes caused tumors in female rats. Years of research led the FDA to find that even though the Russian study was extremely flawed (the FDA couldn’t even prove that amaranth was one of the dyes used), the agency would remove the dye from its Generally Regarded As Safe (GRAS) list in 1976. Between public outcry against the dye and the chance that trace elements could potentially have carcinogens, the FDA banned a number of other dyes as well. According to the FDA, 47 other countries, including Canada and the United Kingdom, still allow for the use of Red Dye No. 2.

That same year, Mars removed their red M&M’s from the candy-color spectrum for nearly a decade, even though Mars didn’t even use Red No. 2; the removal of the red candies was a response to the scare, livescience.com reports:

The red food coloring in question was not actually used in M&M’s chocolate candies, according to mms.com. “However, to avoid consumer confusion, the red candies were pulled from the color mix.”

Inquiries to General Mills as to when the Franken Berry ingredients switched to less poop-worrying dyes, were not responded to. These days, the only red colors accepted by the FDA are Red No. 40, which appears in all five of the General Mills monster cereals, and Red No. 3, typically used in candied fruits.

The symptoms of “Franken Berry Stool” were pretty benign compared to other more notable confectionary mishaps in history: The accidental poisoning of more than 200 people in Bradford, England in 1858 comes to mind. The sweets were accidentally made with arsenic. Let’s be thankful there’s a bit more regulation of food dyes these days.

Another stool scare in cereal history: Smurfberry Crunch Cereal, released in 1982 by Post Foods, turned the poop of those who ate it blue—the ultimate Smurfs experience. Post then changed the formula and re-released the cereal in 1987 as Magic Berries Cereal.

Looking for a sugar high now? You’re safe. When you open your celebratory, Franken Berry or any of the other monster cereals this Halloween, , expect a sugar high—without the pink poop aftermath. We tasted all five of the cereals and Count Chocula is the best by a long shot.

The best part is when the chocolate “sweeties,” as the marshmallows were called in the original commercials in 1971, are all gone: the plain milk becomes chocolate milk. Let’s be real, what child—or “adult”—prefers regular milk to chocolate? I haven’t met this kind of person.