Black Tongues And Stomach Aches

By Danit Brown

Posted October 1, 2020

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Transcript

D: Oh no, Yaël! I think I'm having a medical emergency! Quick, call an ambulance!

Y: A medical emergency, Don? Are you sure? You look fine to me.

D: But I'm not. This morning, I had a terrible stomach ache, and now--now--look at my tongue. AAHHHH! It's all black. Surely I'm dying, and you don't even care.

Y: Relax, Don. Of course I care, but you really aren't dying.

D: But my tongue...

Y: I can tell you exactly what the problem is.

D: You can? But you're not a doctor.

Y: But I do read the contraindications before taking medicine.

D: Huh?

Y: You said you had a stomach ache, right? And I'll bet you five dollars that you took some Pepto Bismol for it?

D: Wow! You must be psychic. How'd you know?

Y: Well, the active ingredient in Pepto Bismol is a compound called bismuth subsalicylate.

D: Bismuth subsalicylate? So?

Y: This compound has anti-diarrheal, anti-bacterial, and antacid effects on the digestive tract.

D: Which is why Pepto helps with stomach discomfort.

Y: Right. But the thing is, when the bismuth combines with the trace amounts of sulfur in your saliva and in your gastrointestinal tract, it reacts to form a black substance called bismuth sulfide.

D: Bismuth sulfide. Sounds dangerous.

Y: It isn't. But that's where the discoloration on your tongue comes from. And bismuth sulfide can also temporarily darken the stool. It's a common enough side-effect that it's listed in the package information, which you really should get in the habit of reading. In a couple of days, everything will be back to normal.

D: Phew, Yaël. You saved my life!

Y: Not really.

The chemical element bismuth extracted from pepto-bismol. (Zaphraud, Wikimedia Commons) (Zaphraud)

Sometimes, when people get stomach aches they are alarmed to find that their tongue has turned black. Fortunately for them, it isn't a life threatening condition.

Pepto Bismol is a commonly used medication for stomach aches, and its active ingredient is a compound called bismuth subsalicylate. This compound has anti-diarrheal, anti-bacterial, and antacid effects on the digestive tract, which is why Pepto helps with stomach discomfort.

However, when the bismuth combines with the trace amounts of sulfur in your saliva and in your gastointestinal tract, it reacts to form a black substance called bismuth sulfide. It isn't dangerous, but that's where the discoloration on your tongue comes from.

Bismuth sulfide can also temporarily darken the stool. It's a common enough side-effect that it's listed in the package information. The black tongue often only takes a couple of days to go back to normal.