Why Your Child May Have a Black Tongue

While there is a condition called black hairy tongue (lingua villosa nigra), which is caused by an overgrowth of bacteria or yeast on the tongue, most kids with a black tongue have a much simpler explanation.

Doctor using tongue depressor to look in girl's mouth
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Bismuth and Black Tongue

Did you give your child Pepto-Bismol recently? Medications like Pepto-Bismol, or other drugs that have bismuth as an ingredient, can cause a black discoloration or staining on your tongue for a few days. It is harmless and goes away a few days after you stop taking the medication.

It occurs when bismuth combines with sulfur, which can sometimes be found in trace amounts in our saliva, forming bismuth sulfide. Since you can also have sulfur in your GI tract, taking medications with bismuth can sometimes also temporarily darken your stool.

Interestingly, many experts think that it is the bacteria in the mouth that are responsible for producing volatile sulfur compounds. That sulfur is one of the things that can lead to bad breath.

Once your child is feeling better, it might be a good time to review his oral hygiene regimen and make sure he is brushing and flossing well and has been to the dentist recently.

Pepto-Bismol and Reye Syndrome

Keep in mind that the main ingredient in Pepto-Bismol, bismuth sub-salicylate, has been linked with Reye's syndrome, a potentially life-threatening disorder that has been associated with kids who take it and also have viral illnesses, especially the flu or chickenpox.

The FDA allows the original Pepto-Bismol (and Kaopectate, which also contains bismuth sub-salicylate) to only include labeling instructions for children over age 12 years, due to the association with Reye's syndrome.

Some doctors go even further and recommend that even teens not take aspirin or salicylate-containing medicines. Since there are alternative medications, why take the risk?

Non-Bismuth Remedies for Kids

There is a version of Pepto, the newer Children's Pepto Chewable Tablets that also help relieve "heartburn, sour stomach, acid indigestion, and upset stomach due to these symptoms or overindulgence in food or drink."

Instead of bismuth sub-salicylate, Children's Pepto Chewable Tablets only contain calcium carbonate as its active ingredient. So, unlike the other forms of Pepto-Bismol, it would not be associated with Reye's syndrome and would be OK for younger children.

In fact, Children's Pepto Chewable Tablets can be given to children as young as age 2 years old. Also, Children's Pepto Chewable Tablets would not be expected to turn your child's tongue black.

Other Causes of Black Tongue

If your child didn't take Pepto-Bismol or another medication with bismuth sub-salicylate that could have turned the tongue black, then you should likely see your pediatrician. Other causes include:

  • A pigmented nevus of the tongue
  • Drinking or eating something with a black dye or food coloring
  • Drinking or eating something with a natural dye, like blackberries

Again, see your pediatrician if your child has a black tongue and hasn't taken medicine with bismuth or if it doesn't quickly go away.

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Article Sources
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  1. Goldman RD. Bismuth salicylate for diarrhea in children. Can Fam Physician. 2013;59(8):843–844. 

  2. Madhushankari GS, Yamunadevi A, Selvamani M, Mohan Kumar KP, Basandi PS. Halitosis - An overview: Part-I - Classification, etiology, and pathophysiology of halitosisJ Pharm Bioallied Sci. 2015;7(Suppl 2):S339–S343. doi:10.4103/0975-7406.163441

  3. Escoto MA. Reye's syndrome. The Nemours Foundation. Updated February, 2019.

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