What Causes a White Tongue?

The top of the tongue is covered in tiny projections that trap debris. When they grow longer or are not worn down by eating and talking, they hold on to dead cells, food, and bacteria, and the tongue looks white or pale yellow, mostly toward the back.

That coating is common in the morning and after illness. It tends to be heavier with dehydration, a dry mouth, mouth breathing or snoring, smoking, a soft diet, and fever. It often comes with a stale taste or bad breath, and our page on bad breath explains why the tongue is a main source of it.

A coating you can wipe or scrape off is the harmless kind. It is a sign of how clean and how wet the mouth is, not of an infection in the body.

Thrush is an overgrowth of a yeast that normally lives in the mouth in small numbers. It appears as creamy white patches on the tongue, inner cheeks or palate that can be wiped off, often leaving a red or sore surface underneath. It may cause a burning feeling, a cotton-wool mouth or a change in taste.

It is more likely after a course of antibiotics, with inhaled steroids for asthma (rinsing the mouth after each use lowers the risk), with diabetes that is not well controlled, with a dry mouth, and in people who wear dentures, especially if worn overnight. Our page on dry mouth covers the last of these causes.

Thrush needs antifungal treatment prescribed by a dentist or doctor, and the reason it happened should be dealt with too. Dentures should be cleaned daily and left out at night.

This is the one to take seriously. A white patch that cannot be scraped off, that has lasted more than two weeks, or that is thick, rough, hard or slowly changing needs examination. Most such patches are harmless thickening of the lining from friction or irritation, but a few are precancerous or early cancer, and you cannot tell by looking.

The risk is much higher with tobacco in any form, including smoking, gutka, khaini and paan with tobacco or areca nut. These are common across Uttar Pradesh, which is why the advice here is more cautious than a general internet answer. A patch that is red as well as white, or any ulcer in the same place, is a stronger reason to be seen.

The dentist examines it, may take a small sample for the lab, and watches it over time. Our page on mouth ulcers explains the three-week rule for sores that do not heal.

For an ordinary coating, clean the tongue once or twice a day. Use a tongue scraper or the back of a toothbrush head, starting as far back as is comfortable and pulling forward with light pressure, rinsing the scraper between strokes. Stop if it gags you or makes the tongue sore. It should not hurt or bleed.

Drink enough water through the day, breathe through the nose where you can, and stop or cut down on smoking and tobacco. Brush the teeth and gum line properly as well, because plaque along the gums feeds the same bacteria, as covered in our guide to removing plaque from teeth. A mouthwash will not clear a coating, as the page on toothpaste and mouthwash for gum disease explains.

Expect a plain coating to improve within a week or two. If it keeps returning, look for the reason, such as a dry mouth, snoring or a medicine, instead of scraping harder.

See a dentist if a white patch does not scrape off, if it has lasted more than two weeks, if it is painful, if it bleeds, or if you use tobacco, gutka or paan and notice any white or red patch. A dentist can also check dentures, sharp teeth and gum health, which are common local causes. If the gums are inflamed too, our gum treatment page shows what the next step is.

See a doctor if the whole mouth keeps getting thrush, if you have had a long antibiotic course, if you have diabetes and your sugar control is poor, or if you feel generally unwell. A baby with white patches in the mouth should be seen by a paediatrician.

Whitish tongue with a sore throat, fever or difficulty swallowing is a medical matter. If swallowing or breathing is affected, go to a hospital emergency department.