Of all the spooky events surrounding Halloween, peering into the toilet bowl and noticing that your poop has turned bright blue might be the scariest. This could be your new reality if you slurp down one of Burger King’s seasonal Scary Black Cherry slushies, Women’s Health points out.


View this post on Instagram

give in to your dark side... scary black cherry now at BK for a limited time.

A post shared by Burger King (@burgerking) on

The black-tinted frozen beverage is made from Fanta soda, and presumably, a fair amount of food dye. Ever since its release ahead of the holiday, customers have been complaining that the drink turned their poo “blackish blue,” neon blue, green, or purple. Similar reports surfaced in 2015 after Burger King introduced a Whopper with a black bun that had been flavored with A.1. Steak Sauce. In that case, customers’ “grass green” bowel movements were blamed on food dye in the bun.

“To make poop turn that color green, it would require far more dye than is in the typical type of A.1.," doctor and nutrition counselor Pamela Reilly told USA Today at the time. "My guess is that they're using a concentrated form."

Although the Scary Black Cherry slushie’s ingredients aren’t listed on the fast food chain’s website, food dye is likely the culprit—once again—of customers' colorful poo. Michigan-based gastroenterologist Michael Rice explained to Women’s Health that food dye mixes with the yellow-green pigments in your bile, which is then excreted in your poop. Darker dyes in particular, like blue and purple, tend to yield the most visible changes in stool color. Beets, licorice, tomato soup, Kool-Aid, Jell-O, candy, and tinted icing can all have the same effect.

From a health perspective, there’s not much to fear, though. Aside from giving you a fright after you go number two, the artificial dyes that Burger King uses are within FDA-approved limits. Your poo should go back to its normal hue in no time.

[h/t Women's Health]