Activated charcoal has been buzzy in the wellness world for years, popping up in a whole bunch of products—from facial cleansers to deodorants—and promising a slew of benefits, from unclogging pores to “detoxing” your body.

Now, we’re seeing it play a different role: turning various foods and drinks pitch-black for Halloween. There are charcoal-colored sprinkle cookies, spooky black margaritas with an orange Tajin rim, charcoal-and-turmeric bagels, and even pumpkin pizza with a charcoal crust. The natural black food coloring seems to turn everything into the perfect shade of inky black.

But the treats may come with an unintended trick: Activated charcoal can interact with certain medications, causing them to work less effectively…or not at all. If you’re thinking about whipping up black cocktails or cupcakes this Halloween, here’s what you need to know about the possible risks of using activated charcoal to get the job done.

What is activated charcoal…and what’s it doing in your icing?

Activated charcoal is a fine black powder that’s made by burning various substances like coconut shells, nut shells, or wood, then “activating” it by heating it along with a gas. This processing creates a bunch of pores in the charcoal, which can help trap chemicals that come into contact with it.

That brings us to its main benefit: “Activated charcoal is sometimes used in the treatment of acute poisonings or after unintended ingestion of medications or other substances,” Sarah Mersek, PharmD, a drug information pharmacist at the Cleveland Clinic, tells SELF. Basically, it soaks up the bad stuff and prevents it from getting absorbed into your bloodstream. The same pores make activated charcoal a helpful ingredient in beauty products, too, since they help substances stick together and “act like a magnet for dirt, oil, and other impurities,” Sejal Shah, MD, a dermatologist at Real Self in New York City, previously told SELF. (What it won’t do? Remove toxins from your body, as SELF debunked back in 2017—your liver and kidneys do a good job of that on their own.)

Then there’s activated charcoal’s most seasonal use as a food coloring. Typically, the powdered form sold for this is made from coconut shells, and its inky, saturated color is simply great for turning things black—a spooky-season benefit that doesn’t have anything to do with its behind-the-scenes absorption work.

What are the potential risks of using activated charcoal in food?

Eating activated charcoal in the short-term is “likely” safe, and consuming it regularly in the long-term is “possibly” safe too, according to the National Institutes of Health. Though in either case, it can cause not-so-pleasant side effects like constipation and black poop.