It is common to have a green tongue after eating or drinking something with green food coloring, but an unexplained color change can be a sign of an underlying issue.
An infection or overgrowth of certain germs is often the cause of a green tongue, though there are other causes as well. Symptoms of a green tongue will usually go away after treating the underlying condition.
In this article, we look at conditions that cause a green tongue, treatment options, and when to see a doctor.
Several conditions may cause a green tongue, including:
1. Oral thrush
In some cases, a buildup of germs or poor oral hygiene may lead to a Candida infection.
Candida albicans is a naturally-occurring yeast that is usually balanced by other bacteria. Oral thrush occurs when this yeast grows uncontrolled in the mouth and on the tongue.
Oral thrush usually gives the tongue a whitish or off-white appearance, but that may change to green over time, depending on how the infection develops. Oral thrush also causes:
- bumps or changes in texture on the tongue or tonsils
- pain in the mouth
- difficulty or pain while swallowing
- bleeding from the bumps if scraped by food, teeth, or a toothbrush
Oral thrush commonly occurs in infants who are breast-feeding. It can cause a similarly discolored tongue, as well as symptoms including irritability and difficulty feeding.
Leukoplakia causes a white patch in the mouth or on the tongue, which may become green or discolored over time. Leukoplakia is often linked to alcohol or tobacco use.
Leukoplakia is typically painless and harmless. Doctors will still want to monitor it regularly as leukoplakia may turn cancerous in some cases.
3. Hairy tongue
Hairy tongue is a harmless condition that causes the tongue’s texture and appearance to change. It occurs because of a buildup of keratin cells, which are the proteins that also make up human hair. This buildup can give the tongue a rough, hairy texture.
This rough surface also provides an excellent area for bacteria and fungi to multiply, which could also cause a green tongue.
Hairy tongue is more common in older people than other people, though it can occur at any age. Hairy tongue may cause other symptoms, including:
- an odd taste on the tongue
- a tickling or gagging sensation that may get worse when swallowing
- bad breath
- difficulty tasting food or changes in the taste buds
Factors that contribute to hair tongue include poor oral hygiene, the use of certain medications, such as antibiotics, or tobacco and caffeine.
4. Geographic tongue
Geographic tongue is a harmless condition that causes irregular blotches to appear on the tongue. These blotches often appear as a dark red spot with a raised white border at first, but they may change color over time.
These lesions may also change shape or location over time and can disappear and reappear often.
Geographic tongue may cause other symptoms, such as a burning sensation in the mouth or discomfort while eating, especially when eating spicy or acidic foods.
The tongue may also become very sensitive to chemicals in oral products and tobacco smoke.
5. Lichen planus
Lichen planus is a disorder of the immune system that can cause a rash on and discoloration of the tongue. The tongue typically turns whitish but may develop a green tint if bacteria or fungi start to grow. Some oral products, foods, and beverages may also be responsible for the color change.
Lichen planus may also cause white lesions in the mouth, which can change color depending on what foods a person has eaten and whether bacteria start to multiply. These lesions may be painful and often cause a burning sensation in the mouth.
Syphilis is a bacterial infection that can be sexually transmitted or passed on from a mother to child during pregnancy.
If a person contracts syphilis from oral sex, they may develop a sore on the tongue that may change color over time. If left untreated, multiple sores may appear in the mouth. Doctors usually prescribe penicillin to treat syphilis.
7. Oral cancer
Although it is much rarer than an oral infection, oral cancer may also cause similar symptoms. One sign of oral cancer is an open sore or lesion on the tongue that does not heal.
This sore may change color depending on the oral products a person uses and the foods and beverages they consume, or if bacteria start to collect.
Oral cancer often causes other symptoms as well, including:
- a growth or uneven area on the tongue
- persistent tongue pain
- bleeding on the tongue or gums with no known cause
- loose teeth
- unexplained weight loss
- colored patches on the tongue that may be green, white, or pinkish
- numbness or tingling sensation in the lips, chin, or neck
- a persistent sore throat or jaw pain
Other possible causes for a green tongue include:
- poor dental hygiene
- throat or upper respiratory infection that spreads to the tongue
- discharge from an infected tongue piercing
- illicit drug use
- temporary color changes caused by food coloring in candy, sweets, or oral hygiene products
- temporary color changes caused by supplements or foods containing chlorophyll
Sometimes, a doctor can diagnose causes of a green tongue with a simple visual examination. A doctor will also ask a person about their symptoms and may look for other signs of an infection.
A biopsy is often only necessary if a doctor suspects that there is a chance of cancer somewhere on the tongue. They may also use one or more imaging tests to see if cancer cells have spread.
Treatment for a green tongue will vary depending on the underlying cause. Doctors may recommend antibiotics if they are confident the green tongue is caused by bacteria.
If a doctor suspects a fungal infection, they may recommend antifungal medications, such as nystatin, fluconazole, or clotrimazole.
Oral leukoplakia may be treated with vitamin A or retinoids, but treatment does not always resolve symptoms.
Antihistamines or corticosteroids can help treat inflammation in the tongue or mouth. Over-the-counter pain relievers, such as ibuprofen (Advil) or acetaminophen (Tylenol), may also provide some relief, depending on a person’s symptoms.
Treatment for oral cancer treatment varies between individuals and may include nutritional changes, chemotherapy, and surgery.
In all cases of green tongue, proper oral hygiene is essential to support treatment efforts. Steps a person can take to encourage healing include:
- brushing teeth and tongue regularly
- flossing daily to reduce bacteria in the mouthbrushing and flossing gently to avoid causing any cuts in the mouth
- avoiding mouthwashes that contain harsh chemicals or high alcohol levels
- rinsing the mouth regularly with saltwater
- drinking plenty of water
Some doctors may also recommend eating probiotic foods or supplements to increase the number of good bacteria in the body.
Tongue scraping may also help reduce the number of germs on the tongue and in the mouth that contribute to oral issues.
Tongue scraping is not a cure for a green tongue but may help support a doctor-recommended medication or treatment plan.
Tongue scraping may work best when added to a daily oral hygiene routine, along with brushing and flossing.
It is best to ask a doctor or dentist about tongue scraping before starting, as it may not be helpful in every case.
When not caused by temporary staining from food coloring, green tongue is often a sign of an overgrowth of harmful germs in the mouth.
Whether this is a yeast overgrowth or another type of infection, it is essential to see a doctor for treatment if the discoloration does not resolve in a few days or goes away and comes back.
Many cases of green tongue require medical treatment. Following the treatment plan set out by the doctor is the best way to resolve the underlying issue.