Your tongue is a muscle that’s covered in pink tissue called mucosa and tiny bumps called papillae, which are covered in thousands of taste buds. It may surprise you, but the color of your tongue can provide insight into your health.

While certain foods and drinks — along with chewing tobacco — can cause tongue discoloration, bacteria on the tongue and some medical conditions can also cause changes to your tongue’s color.

A purple tongue or one with a blueish tint could indicate a problem with your health, from a vitamin deficiency to adrenal gland problem. It can also be a sign of insufficient oxygen in the blood, which is a medical emergency.

The most common cause of a purple tongue is staining from certain foods and beverages. Some of the things you might consume that could cause your tongue to appear purple include:

  • certain juices or beverages, such as grape juice
  • blueberries
  • beets, including beet juice and beet chips
  • purple or blue popsicles, or frozen treats
  • colored frosting or icing
  • colored candy

If you haven’t had anything to eat or drink that would stain your tongue, the following are health issues that may cause your tongue to appear purple or blue:

Blood circulation problems

A purple or blue tongue could be a sign that your blood isn’t delivering enough oxygen to your body’s tissues. Or, that oxygen-depleted blood — which is dark red, rather than bright red — is circulating through your arteries.

The blueish discoloration that occurs due to this is called cyanosis. Cyanosis can be caused by issues that affect the lung or heart, such as coronary artery disease or chronic obstructive pulmonary disease (COPD). This blueish tint may happen in more places than just your tongue.

Your tongue can also turn blue or purple because of lack of oxygen due to an airway obstruction.

In these situations, a purple or blue tongue is a medical emergency. Call 911 and seek emergency medical attention if your tongue discoloration comes on suddenly or is accompanied by any of the following symptoms:

  • gasping for breath
  • breathing difficulties
  • chest pain
  • dizziness or fainting

Vitamin B-2 deficiency

Vitamin B-2 — also known as riboflavin — is a water-soluble vitamin. Milk and dairy products are high in riboflavin, along with meat, fish, and certain fruits and vegetables.

Vitamin B-2 deficiency isn’t very common in Western countries. When it does occur, it’s been linked to several health issues, including anemia. This condition can affect your mucus membranes, including the tongue, causing swelling and discoloration.

Along with anemia and a purplish tongue, other signs and symptoms of a vitamin B-2 deficiency include:

Bacteria

According to a 2017 study, more than 25,000 types of bacteria can be found on your tongue and throughout the rest of your mouth. Not all bacteria are bad, and some of it’s even necessary for your oral health.

But depending on the type, abnormally high numbers of certain bacteria may cause tongue discoloration — though a white film coating on the tongue is more common than purple or any other color.

Gently brushing your tongue using your toothbrush or a tongue scraper can get rid of this harmless coating and help remove and prevent the buildup of bacteria, dead cells, and other debris.

See your dentist if you have tongue coating, tongue discoloration, or any pain.

Varicose veins

Sublingual varices are varicose veins of the tongue. They’re purple or blue and can be seen running along the underside and sides of your tongue. They usually develop and become more prominent with age.

Though common and not usually a cause for concern, sublingual varices may be linked to high blood pressure, according to one 2014 study.

Addison’s disease

Also called adrenal insufficiency, Addison’s disease occurs when your adrenal glands don’t produce enough of certain hormones, including cortisol or aldosterone.

Symptoms usually develop slowly and may include a purple tongue. Though brown or tan spots are more common, a 2014 case report of a person who presented with a blueish tongue suggests that Addison’s disease could cause the tongue to appear other colors.

Other signs and symptoms of Addison’s disease may include:

  • darkening of the skin
  • extreme fatigue
  • weight loss

Certain medications

Medications that contain bismuth, such as Pepto-Bismol, can cause tongue discoloration that may appear dark purple or black. It can also cause dark stools. This usually clears up on its own within a few days of stopping the medication.

Tumors

Hemangioma is a noncancerous tumor of dilated blood vessels. Though not very common, they can occur in the oral cavity, including on the tongue.

It produces a purple swelling that looks like a raised bruise or purple bump on the tongue.

Any new growth on your tongue should be evaluated by a dentist. A biopsy may be needed to diagnose any lesions and rule out oral cancer.

The Oral Cancer Foundation recommends having any lump, sore, or discoloration that doesn’t heal within 14 days looked at by a professional.

Other symptoms of oral cancer may include:

  • pain
  • trouble chewing, swallowing, or speaking
  • hoarseness
  • swollen lymph nodes in the neck
  • a persistent earache

Tongue discoloration that isn’t linked to something you’ve had to eat or drink should be discussed with a doctor.

Seek emergency medical treatment if your tongue turns purple suddenly or is accompanied by:

  • chest pain
  • profuse sweating
  • difficulty breathing
  • choking
  • dizziness
  • low blood pressure
  • loss of consciousness

Treatment will depend on the cause of your tongue discoloration.

Tongue discoloration can be caused by a number of things, ranging from something you’ve eaten to a serious medical condition. Staining from certain foods and drinks, such as blueberries or beets, is the most common cause of a purple tongue.

If your tongue discoloration can’t be linked to something you’ve consumed or if you’re concerned about changes to your tongue’s appearance, see your dentist or doctor.