Specialties & Diseases > Gastroenterology

The surprising link between tongue health and digestion

By MDLinx staff

Published April 2, 2025

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“A healthy tongue should be pink, smooth, and wet. A whiter brown coating could be gut dysbiosis, smoking, alcohol consumption, coffee, [or] medications.” — Staci Whitman, DMD

Find more of your peers' perspectives and insights below.

As doctors, we’re trained to look at the big picture, but sometimes the smallest signs can reveal important clues about a patient's health. One of those signs? Their tongue.

A recent Instagram Reel from board-certified functional dentist Staci Whitman, DMD, got me thinking about how changes to the tongue can point to something going on in the gut. A coated tongue isn’t just a sign of poor oral hygiene—it could actually be a red flag for gut issues like imbalanced bacteria or even yeast overgrowth.

When we look at a healthy tongue, we expect it to be pink with a thin white coating. But if it’s thick, yellow, or white, it could indicate digestive problems like IBS or leaky gut syndrome. This is because an imbalance in gut bacteria often shows up on the tongue.

Here are some other signs to watch for:

Red and Inflamed Tongue: A tongue that’s bright red and inflamed could point to B vitamin deficiencies, especially B12, or iron deficiency anemia. It can also be a sign of autoimmune gut disorders like Crohn’s disease.^[]
Cracked Tongue: Cracks, particularly on the sides, might be a sign of dehydration or nutritional deficiencies. It could also indicate oral thrush or candida overgrowth, both linked to gut imbalances. ^[]
Purple or Dark Tongue: If a tongue looks purple or dark, it might be pointing to poor circulation, or it could indicate liver problems or chronic digestive issues. It’s also worth checking for iron or B12 deficiencies. ^[]
Fungal Infections: A white, thick coating might suggest a yeast infection, like oral thrush, which is often linked to gut yeast imbalances. ^[]

It’s a simple yet powerful reminder that we need to pay attention to the subtle signals our patients' bodies are sending. A white or coated tongue might be telling us more than just "brush me." If you see these signs and your patient also has digestive complaints, it might be time to dig a little deeper into their gut health.

So next time you’re doing an exam, take a quick look at the tongue. It could be giving you important clues about what's happening inside the gut—and early intervention could make all the difference for your patients.