Ingesting foods that contain artificial food dyes can lead to rainbow poops, according to Cleveland Clinic experts. In other words, you may look down after using the bathroom and see any possible color. These kinds of foods include powdered drink mixes, popsicles, icing, or multi-colored candies, just to name a few (via Mayo Clinic). Green dye #3 and Red dye #40 are two examples of such artificial ingredients that can be found in foods like Jell-O or Froot Loops cereal (via Muscle and Fitness).
If you grew up in the early 70s, you might remember Franken Berry, a popular children’s cereal released just in time for spooky season (via Smithsonian Magazine). Many consumers, particularly kids, soon developed a side effect nicknamed “Franken Berry Stool,” in which fans of the cereal produced bright pink poops due to the Red dye No. 2 and No. 3 ingredients. While Red No. 2 has since been banned in the U.S., Red No. 3 is still permitted for use in foods except in the state of California (via NBC News). Other rainbow poop-producing cereals that emerged on the market over the years included General Mills’ Boo Berry and Post Cereal’s Smurfberry Crunch. Although many of these products have since been discontinued, NPR reported in 2022 that both Franken Berry and Boo Berry returned to store shelves during the month of October for a limited-edition walk down memory lane.