Your tongue is one place where you might develop symptoms if you’re mildly dehydrated. Some tongues develop white patches or a dry, rough surface.

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About 60 percent of your body weight comes from water. Dehydration occurs when your body losses water faster than you’re able to replenish it.

Dehydration causes changes to many tissues in your body. In the early stages, you may develop symptoms such as a dry mouth, thirst, and light-headedness. Severe dehydration can cause organ failure and death.

Along with dehydration, having a white tongue can also be a sign of many other medical conditions. Most of these conditions aren’t severe, but some require prompt medical attention.

Let’s look at some of the tongue symptoms that may indicate you’re dehydrated and examine other causes of a white tongue.

Every cell in your body requires water to function. If you lose more water than you take in, your cells won’t have enough fluid to work correctly. Severe dehydration can lead to organ failure and other serious complications.

Your tongue is a muscular organ covered in tiny bumps called papillae. These bumps contain receptors that allow you to taste your food.

Dehydration can lead to reduced saliva production. One of the roles of your saliva is to help maintain your oral hygiene. Your saliva contains antimicrobial substances such as hydrogen peroxide, lactoferrin, and lysozyme, which help reduce levels of yeast and bacteria in your mouth.

A dry mouth can increase your risk of infections like oral candidiasis, also known as oral thrush. Oral thrush is a yeast infection that commonly causes a white patch over the papillae on your tongue. It can also occur on:

  • your inner cheeks
  • the roof of your mouth
  • gums
  • tonsils

A dry mouth can also contribute to swelling of your papillae. The following can get stuck around the enlarged papillae and give your tongue a white appearance:

  • bacteria
  • fungi
  • dead cells
  • food

Dehydration can cause several symptoms that affect your mouth and tongue. People often report their tongues having a dry, rough texture when they’re dehydrated.

Other symptoms affecting the mouth and tongue can include:

  • dry lips or tongue
  • dry mouth
  • sticky mouth
  • lack of salivia production

A dehydrated tongue or mouth is an indication that your entire body is dehydrated. Other early warning signs of dehydration are:

Here’s a look at what a rough, white tongue caused by dehydration looks like:

According to St. John Ambulance, here are some steps to follow if you’re with someone who becomes dehydrated.

  1. Help them sit down.
  2. Give them water by itself or with an oral rehydration solution, if available. Avoid giving them cooking salt mixed with water.
  3. If they have muscle cramps, encourage them to rest. You can also help them massage or stretch their cramping muscles.
  4. Monitor their level of responsiveness. If they continue to seem unwell, seek medical treatment.

If you’re mildly dehydrated, drinking plenty of fluids might be enough to treat your symptoms. If drinking fluids doesn’t make you feel better, it’s a good idea to seek medical treatment. You should also seek medical treatment if your baby or toddler is dehydrated.

Medical emergency

Emergency symptoms that should prompt you to go the nearest emergency room or call 911 include:

A white tongue can be a sign of many other conditions, including the following.

Poor oral hygiene

Poor oral hygiene is one of the most common causes of a white or grayish color on your tongue. Contributing factors include:

  • dehydration
  • tobacco use
  • overconsumption of alcohol
  • not brushing your teeth frequently
  • eating too much sugar

Poor oral hygiene can lead to the bumps on your tongue becoming inflamed and swollen. Food particles, microbes, and dead cells can stick to these inflamed bumps and make them appear white.

Geographic tongue

Geographic tongue is a harmless, chronic inflammatory condition of the mouth. It’s unknown what causes geographic tongue, but it affects about 1 to 2.5 percent of people and about 39.4 percent of people in their 20s and is more common in women.

It’s characterized by the development of smooth red patches with white borders on your tongue that gives it a “map-like” appearance.

Oral thrush

Oral thrush is a yeast infection in your mouth. It’s most common in children and people with suppressed immune systems, such as people undergoing cancer treatment or who have HIV. Oral thrush also commonly develops in people taking antibiotics.

Also, oral thrust is common in people who use steroid inhalers for asthma or chronic obstructive pulmonary disease (COPD). Rinsing your mouth after using inhalers might prevent thrush.

Oral thrush usually isn’t serious. It’s characterized by white patches that develop on your tongue or other parts of your mouth. It often also causes a bad taste.


Leukoplakia is a condition that causes white or gray patches on your tongue and in your mouth. It’s most often linked to tobacco or alcohol use. The patches are usually harmless, but a history of leukoplakia is linked to the development of oral cancer.

You should see a doctor if you think you have leukoplakia to rule out more serious conditions and to keep the patches from getting worse.

Oral lichen planus

Lichen planus is a rash that results from an immune response, although the exact cause isn’t known. It can form in any part of your body. When it forms in your mouth, it’s called oral lichen planus. It often causes symptoms such as:

  • white patches
  • open sores
  • swelling
  • ulcers

White patches often appear as tender spiderweb patterns that may develop into open sores. Treatment usually includes corticosteroids.

Oral syphilis

Syphilis is a sexually transmitted infection (STI) caused by bacteria. If syphilis is transmitted during oral sex, it can cause symptoms that affect your mouth. In the early stages, it may cause white or grayish sores. The most commonly appear on your:

  • lips
  • inner lips
  • tongue
  • palate

When to see a doctor if you think you may have syphilis

Syphilis can be treated relatively easily with antibiotics in the early stages. However, if left untreated, it can cause long-term organ damage, even after the sores disappear.

The initial symptom is usually the formation of a canker sore somewhere in your mouth. The next symptoms to appear often include:

  • rash
  • swollen lymph nodes
  • fever
  • sore throat
  • headache
  • weight loss
  • large, raised sores

If you’re diagnosed with syphilis, it’s important to tell all of your sexual partners to get tested and treated to reduce the chances of spreading the STI.

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Tongue cancer

The first noticeable symptom of tongue cancer is often a sore that doesn’t heal and bleeds easily. Tongue cancer also commonly causes a persistent red or white patch.

The two greatest risk factors for developing tongue cancer are heavy alcohol use and heavy smoking.

When to see a doctor if you think you may have tongue cancer

Tongue cancer is a serious condition that requires immediate medical attention. Some of the warning signs of tongue cancer that should raise concern include:

  • red or white patch that doesn’t go away
  • bleeding for no apparent reason
  • pain when swallowing
  • persistent ulcer
  • persistent lump in your throat
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If you’re dehydrated, you may notice your tongue has a rough surface or it develops a white layer. Most causes of a white tongue aren’t serious. Poor oral hygiene is one of the most common causes of a white tongue and can be cleared up by improving oral health habits.

In rarer cases, a white tongue can be a symptom of a potentially serious disease such as syphilis or oral cancer. If you have any of the warning signs of these conditions, you should see a doctor promptly.