Dog’s Tongue is Blue: Unraveling the Mystery behind the Hue

Dog's Tongue is Blue

A blue tongue in dogs can be a surprising and puzzling sight for pet parents. While some breeds may naturally have a bluish tint to their tongues, this unusual color change can also signal a cause for concern.

Understanding the potential reasons behind your canine companion’s blue tongue and knowing when to seek professional help can make a world of difference for your furry friend’s well-being.

Just like our own tongues, a dog’s tongue can reveal clues about their overall health. The normal hue for your pup’s tongue varies from pink to bluish-black, depending on the breed. However, when their tongue takes on a blue or purple shade, it could be a sign of an underlying medical issue. Causes can range from lack of oxygen in the blood to heart and lung complications.

This Shar Pei has a naturally blue tongue

In this article, we’ll delve into the fascinating world of dog tongue color variations, uncovering possible reasons behind your pet’s blue tongue, and discussing what to do when faced with such a scenario. Armed with this knowledge, you’ll be better equipped to keep your four-legged friend healthy and happy.

While we have listed all of the common causes of a blue tongue in dogs, and linked to appropriated medical literature to help you get a better understanding of what could be happening to your dog, we recommend you call the vet if your dog’s tongue suddenly turns blue.

Key Points

  • A blue tongue in dogs can be a sign of cyanosis, which is a lack of oxygen in the blood.
  • Cyanosis can be caused by various factors such as heart or lung disease, poisoning, or injury.
  • Other symptoms may include difficulty breathing, lethargy, and collapse.
  • Immediate veterinary attention is necessary if a dog shows signs of cyanosis.

Causes of Blue Tongue in Dogs

Causes of Blue Tongue in Dogs

A blue tongue in dogs, also known as cyanosis, is an indication of insufficient oxygen levels in the blood. This alarming symptom could be caused by various underlying health issues, which we will discuss in the following subsections.

Congenital Heart Disease

Congenital heart diseases are heart abnormalities present at birth, affecting the structure or function of the heart. In some cases, this can lead to reduced oxygen levels, causing a dog’s tongue to appear blue. Common congenital heart defects in dogs include:

  • Patent ductus arteriosus (PDA)
  • Aortic stenosis
  • Pulmonic stenosis
  • Ventricular septal defect (VSD)


Pneumonia is an infection of the lungs, resulting in impaired gas exchange, which can in turn, reduce oxygen levels in the blood. Symptoms of pneumonia in dogs include:

  • Coughing
  • Difficulty breathing
  • Nasal discharge
  • Fever
  • Lethargy
  • Loss of appetite


Asthma in dogs, similar to humans, is an inflammatory condition of the airways, making it difficult for the dog to breathe. Swelling and narrowing of the airways reduce oxygen intake, leading to cyanosis.


Hypothermia occurs when a dog’s body temperature drops significantly below the normal range. Severe hypothermia can lead to reduced blood flow and insufficient oxygen supply to the tissues, resulting in a blue tongue.

Blunt Force Trauma

Blunt force trauma, such as a collision with a car or a fall, can cause injuries to a dog’s chest, resulting in bruising of the lung tissue or blood vessels. This can impair the lung’s ability to oxygenate blood, causing cyanosis.


Pneumothorax is the accumulation of air in the pleural cavity, the space surrounding the lungs. This build-up of air can cause the lung to collapse, making it difficult for the dog to breathe and reducing oxygen levels in the blood.

Pleural Effusion

Pleural effusion is the build-up of fluid in the pleural cavity. This fluid can compress the lungs, making it difficult for the dog to breathe and reducing the oxygen level in the blood. Causes of pleural effusion in dogs include:

  • Infections
  • Heart failure
  • Cancer
  • Trauma

Remember, a blue tongue is a sign that your dog needs urgent medical attention. If you notice this symptom in your pet, consult your veterinarian immediately.

Toxic Substances and Blue Tongue

Ingested Poisons

Call the pet poison control hotline if you suspect your dog has ingested poison: (888) 426-4435

A dog’s tongue turning blue is usually a sign of cyanosis, which indicates a lack of oxygen in the blood. This can happen if your dog ingests certain toxic substances. For example, when a dog consumes rat poison or metaldehyde (found in some snail and slug baits), their tongue may turn blue due to the poisoning.

If you suspect that your dog has consumed a poisonous substance, it’s essential to seek veterinary care immediately. Time is of the essence, and the faster you act, the better the chances of your dog making a full recovery.

Here are some common poisonous substances known to cause a blue tongue in dogs:

  • Rat poison: Contains anticoagulants that disrupt blood clotting, leading to internal bleeding and eventually cyanosis.
  • Metaldehyde: A chemical found in snail and slug baits that affects the nervous system and can cause oxygen deprivation.
  • Smoke inhalation: Dogs exposed to heavy smoke from fires might have a blue tongue due to the lack of oxygen in the air.

Bacterial Infections

Aside from ingesting toxic substances, bacterial infections can also contribute to a dog’s tongue turning blue. A severe infection might decrease oxygen levels in the blood, causing cyanosis and a darker hue on their tongue.

Such infections can result from multiple factors, including poor oral hygiene, pre-existing health conditions, or exposure to contaminated water or food. It is important to identify the cause and treat it accordingly to prevent any further complications.

To sum up, pay attention to your dog’s tongue color as it might indicate an underlying health issue related to toxic substances or bacterial infections. If you notice a sudden change in color, especially if it shifts to blue, seek veterinary assistance immediately to ensure your dog’s safety and well-being.

Organ-Related Causes

Is a blue tongue normal in dogs?

Liver and Kidney Malfunction

When your dog’s tongue is blue, it could be a sign of organ-related issues, particularly liver and kidney malfunction. The liver and kidneys are crucial in filtering toxins and maintaining overall health. When these organs are under stress or not functioning optimally, it may result in a blue-toned tongue. Liver disease, for example, might cause an increase in bilirubin levels, which can alter the color of your dog’s tongue. Similarly, if kidney problems are present, the buildup of waste products in your dog’s system might contribute to a blue tongue.


Anemia, or a low red blood cell count, is another potential cause for a blue-tinted tongue in dogs. Red blood cells are responsible for transporting oxygen throughout the body, and when these levels are low, it can lead to cyanosis—a condition where there’s inadequate oxygen supply in the blood. This lack of oxygen in your dog’s blood could cause their tongue to appear blue, indicating an anemic condition.

Internal Bleeding

Internal bleeding, although a rare occurrence, might also contribute to a blue-toned tongue in dogs. When blood loss occurs inside the body, it can lead to a decrease in oxygen levels, causing a dog’s tongue to turn blue. This is usually accompanied by other symptoms such as weakness and lethargy. In such cases, it’s crucial to seek veterinary assistance promptly to address the underlying cause of the internal bleeding.

Inflammation and Blue Tongue

Inflammation is a common occurrence that may lead to a blue hue in a dog’s tongue. Often, this color change can be traced back to issues with the gums, mucous membranes, or salivary glands. A bacterial infection, foreign body obstruction, or even heatstroke can cause inflammation and result in your dog’s tongue turning blue.

If your dog’s tongue appears blue, it’s essential to watch out for warning signs such as trouble breathing or difficulty eating, as these can signal a more severe issue. Note that a blue tongue indicates insufficient oxygenation of the blood, a serious concern that must be addressed promptly.

Prevention plays a crucial role in avoiding inflammation-induced blue tongue. Timely identification of any foreign body or bacterial infection will help ensure that your dog maintains good oral hygiene. Regular veterinary check-ups are invaluable, and keeping an eye on your dog’s behavior and physical condition can catch early signs of a problem.

In addition, make sure your dog has access to fresh water and stays cool in hot weather, as heatstroke is another factor that can contribute to inflammation and a blue tongue. If you notice your dog becoming overheated, move them to a cool and shaded area to help reduce the risk of heatstroke.

Dog Breeds with Naturally Blue or Purple Tongues

Chow Chows

Dog breeds with naturally blue tongues

The Chow Chow is a distinct dog breed that’s commonly recognized for its fascinating purple tongue. The origin of their tongue coloration remains a mystery, but it does make this breed quite striking. Although Chow Chows are born with pink tongues like other dog breeds, their tongues gradually transform into a more purple hue as they mature. Genetics play a significant role in determining the specific color and pattern of a Chow Chow’s tongue, with some dogs boasting completely purple tongues, while others have a mix of purple and blue-black dots.

It’s important to note that Chow Chows are not the only dog breed with naturally pigmented tongues, but they are definitely one of the most well-known breeds for this characteristic.


Another dog breed with a naturally blue or purple shade on their tongues is the Chinese Shar-Pei. Their blue-black tongue is an ideal complement to their unique wrinkled, loose skin and distinctive “hippopotamus” face. Like Chow Chows, a Shar-Pei’s tongue color is rooted in genetics, which determines whether the tongue will be solid blue-black or if it will feature spots.

Chinese Shar-Peis are closely related to Chow Chows in terms of their genetic makeup, which explains the reason behind their shared distinctive tongue coloration.

Frequently Asked Questions

What can cause a dog’s tongue to change color?

A dog’s tongue can change color for several reasons. The most concerning cause is a lack of oxygen in the bloodstream, also known as cyanosis, which can lead to a blue or purple tongue. Some other causes of color changes are infections, injuries, poor circulation, or even certain medications. It’s important to monitor your dog’s tongue color and consult a veterinarian if you notice any significant changes.

Why does a dog’s tongue turn blue when oxygen is low?

When oxygen levels are low in a dog’s bloodstream, their tongue may turn blue or purple. This is a result of hemoglobin, the protein found in red blood cells responsible for transporting oxygen, not receiving adequate oxygen. Consequently, the blood’s color changes and causes the tongue to appear bluish-purple.

What is the meaning behind a purple tongue in dogs?

A purple tongue in dogs generally signifies a lack of oxygen in the bloodstream (cyanosis). This can be due to various reasons, such as heart or lung issues, blood clots, or even anemia. It’s essential to consult a veterinarian if you notice a purple tongue in your dog, as it could be indicative of a serious health problem.

How serious is cyanosis in dogs and its treatment?

Cyanosis in dogs is a serious medical condition, and prompt action should be taken. The severity and treatment of cyanosis depend on the underlying cause. Treatment may include oxygen therapy, medications, or surgical intervention, depending on the cause. It is crucial to address cyanosis as soon as possible to prevent severe consequences or even death.

Are blue spots on a dog’s skin and stomach normal?

Blue spots on a dog’s skin and stomach can be a cause for concern. They may result from bruising, blood spots, or pigmentation changes. It’s important to carefully monitor your dog’s skin and consult a veterinarian if you notice any unusual color changes, as it could indicate an underlying health issue.

What are symptoms of oxygen deprivation in dogs?

Symptoms of oxygen deprivation in dogs can include rapid or labored breathing, coughing, disorientation, weakness, fatigue, pale or blue gums and tongue, and even collapse. If you notice any of these symptoms in your dog, seek immediate veterinary care, as oxygen deprivation can cause critical health problems or even be fatal.