Pepto Bismol causes black tongue due to a chemical reaction between its active ingredient, bismuth subsalicylate, and sulfur compounds in the mouth. This reaction produces bismuth sulfide, a black compound that temporarily coats the tongue and can also darken stool. The staining is harmless and usually goes away after stopping the medication.
Cause of Black Tongue
The black discoloration happens when bismuth from Pepto Bismol reacts with sulfur-containing compounds produced by bacteria in the mouth, forming black bismuth sulfide. This compound adheres to the tongue's surface and may also bind to the tongue’s papillae, causing the distinct black staining effect.
Mechanism
When bismuth subsalicylate is ingested, it interacts specifically with hydrogen sulfide gas from oral bacteria. This forms bismuth sulfide, which adheres to the tongue’s surface, creating the black color.
Effects and Duration
This effect is temporary and harmless. It resolves after the medication is metabolized and eliminated from the body, usually within a few days. If the discoloration persists beyond several days after stopping Pepto Bismol or is accompanied by other symptoms, medical advice is recommended.
Managing Black Tongue
Good oral hygiene, rinsing the mouth after taking Pepto Bismol, staying hydrated, and avoiding staining beverages like coffee and tea can help reduce the black discoloration and speed recovery.
