It's frequently used to make food appear black. It has some legitimate uses but food shouldn't be one of them.

https://en.wikipedia.org/wiki/Charcoal_in_food

Why burn your food for that harsh crunchy texture? Just eat activated charcoal instead, no need to spend all that time and money burning food, just pure taste sensation!

Years ago it was a trend to put activated charcoal in stuff like toothpaste and milk based coffee drinks.

Do you guys not take it against gas? That's a common item in medicine cabinets where I am.