Be aware...a certain pink liquid could give you a black tongue.
It starts with a tummy ache...then you grab the Pepto Bismol, or any over the counter remedy that contains bismuth. For some people, that ingredient will turn your tongue black.
The Academy of General Dentistry says its a common chemical reaction. When the bismuth mixes with a small amount of sulfur in the mouth, it can trigger a temporary black discoloration. It can even happen with some antibiotics.
It's harmless, but if the discoloration doesn't go away, you should take your tongue to the doctor.