Changes in Mucous Membrane Color: What Can Your Dog’s Gums And Tongue Tell You?

Do you know what is your dog’s normal gum color?

In Traditional Chinese Veterinary Medicine, the tongue provides a wealth of information about a dog’s health status. Tongue diagnosis is quite fascinating. The veterinarian gains insight from the tongue color, coating, and even shape. Each section of the tongue reflects the function of a different internal system.

More information: You want to see my what? — Traditional Chinese Veterinary Medicine & Tongue Diagnosis

Today I want to talk about some vital, basic information you can gain from observing your dog’s gums and tongue.

Changes in Mucous Membrane Color: What Can Your Dog's Gums And Tongue Tell You?


During hot summer months, I pay close attention to the color of my dogs’ mucous membranes. Make no mistake, heat stroke is a deadly summer danger.

As soon as my dogs’ tongue and gums start getting deeper pink, it signals to me that it is time to take a break and cool down. I am very paranoid about this and watch closely to register even subtle changes.

As the dog’s body gets hotter, the pink gets progressively darker.

Eventually, the tongue may turn brick red or even purple or blue as oxygen saturation declines. These are signs of an emergency and you don’t want to let things get that far.

Another sign that your dog is getting too hot is increased panting. I noticed that even with seemingly typical panting (as in play), when my guys are getting warmer, they hold their tongues out further and wider than usual. That again is a sign to me that it’s time to take a break and cool down.

At early stages, these changes can be fairly subtle but I like to take precautions sooner rather than later. During a walk on a hot day—we do go out either in the morning or evening but even then the temperatures can be pretty high—I will stare at Jasmine’s tongue and gums constantly, often tripping and stumbling over things, that’s how important this is to me.

Be diligent

I always carry plenty of water, not only for drinking but enough to be able to wet my guys down if necessary.

Tongues that are even a couple of shades darker than normal are enough for me to take action.

Only once, a couple of years back, Jasmine’s tongue and gums started turning red on the drive home, and it almost threw me into a panic. Fortunately, getting her to drink a bunch of water and wetting her body was enough to cool her down and nothing bad came from it.

Jasmine did once suffer severe effects from hyperthermia—it was drug-induced hyperthermia—and the outcome was quite devastating.

Don’t ever underestimate the damage heatstroke can cause to your dog’s body. Pay attention and don’t wait for further symptoms to develop.

Other serious conditions

There are other serious conditions that can cause your dog’s mucous membranes to change from their normal appearance.

It is always important to consider circumstances and accompanying symptoms.

Mucous membranes that are bright red, pale, white, yellow, orange, blue or purple indicate a serious medical problem.

Bright red color

Besides heat stroke, bright red color might indicate:

  • fever
  • severe infection
  • poisoning
  • smoke inhalation
  • abnormal levels of red blood cells, which can be caused by dehydration, chronically low blood oxygen levels or bone marrow disease

Blue or purple

Blue or purple membranes indicate a lack of oxygen, which can be caused by heart failure, poisonings, or respiratory problems.

Yellow or orange

Yellow or orange membranes (i.e., jaundice) are typically associated with liver disease/jaundice or red blood cell disorders.

Pale, gray, or white

Pale, gray or white membranes can be a sign of anemia, shock, blood loss or, severe dehydration, and more.


Gums with little bruises may indicate a blood clotting problem.

All of these changes indicate serious medical conditions which require immediate veterinary attention.

Signs of dehydration

Other things you can check by examining your dog’s gums are capillary refill time and level of dehydration/hydration status.

Dry, sticky gums are a sign of dehydration. This is particularly important when your dog is suffering from vomiting or diarrhea or has stopped eating or drinking.

Slow capillary refill time is another sign of a critical illness. To check this, press a finger firmly on the dog’s gums for about three seconds. The area you pressed on will be paler than the surrounding tissue. The color should return to normal in about one and a half seconds. If it takes longer than that, it could be a sign of low blood pressure or poor circulation (e.g., from heart disease or dehydration), another indication that your dog is really sick.

Know what is the normal color of your dog’s tongue and gums is and pay attention to any changes.

Dental disease

While looking at your dog’s oral mucous membranes you might see red and swollen gums from bacterial infection, such as gingivitis. White spots can mean oral thrush – a fungal infection. Any new lumps, bumps, growths or local discolorations, particularly darkly pigmented areas, of the mouth, tongue, and gums should also be examined by your veterinarian.

When was the last time you took a good look at your dog’s mouth?

Related articles:
Dog Skin Pigmentation Changes: Why Has My Dog’s Skin Changed Color?

Further reading:
Normal Vital Signs

Categories: Color of gums and tongue

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Jana Rade edited by Dr. Joanna Paul BSc BVSc

I am a graphic designer, dog health advocate, writer, and author. Jasmine, the Rottweiler of my life, was the largest female from her litter. We thought we were getting a healthy dog. Getting a puppy from a backyard breeder was our first mistake. Countless veterinary visits without a diagnosis or useful treatment later, I realized that I had to take Jasmine's health care in my own hands. I learned the hard way that merely seeing a vet is not always enough. There is more to finding a good vet than finding the closest clinic down the street. And, sadly, there is more to advocating for your dog's health than visiting a veterinarian. It should be enough, but it often is not. With Jasmine, it took five years to get a diagnosis. Unfortunately, other problems had snowballed for that in the meantime. Jasmine's health challenges became a crash course in understanding dog health issues and how to go about getting a proper diagnosis and treatment. I had to learn, and I had to learn fast. Helping others through my challenges and experience has become my mission and Jasmine's legacy. I now try to help people how to recognize and understand signs of illness in their dogs, how to work with their veterinarian, and when to seek a second opinion. My goal is to save others the steep curve of having to learn things the hard way as I did. That is the mission behind my blog and behind my writing. That is why I wrote Symptoms to Watch for in Your Dog, which has turned out being an award-winning guide to dog owners. What I'm trying to share encompasses 20 years of experience. Dr. Joanna Paul BSc BVSc is our wonderful sponsor and has been kind to edit and fact-check my important articles.

  1. This is important information to know. I do check my dogs’ gums, especially when it is hot out or they seem to be panting for an unknown reason.

    • Gum color is an essential indicator. Not only when the dog is panting a lot and might be suffering from a heat stroke but also when they are lethargic or look and act very ill.

  2. nancytsocial

    Very timely post as the heat turns up here. Makes sense! I had not thought to examine gums as an indicator.

  3. I had to worry about Brulee’s gums this past week. She developed a terrible URI and had a fever and was vomiting. Thankfully, with some fluids, antibiotics, and anti-nausea meds,she is on the mend.

  4. Whenever I am out and about with Layla I have water for her, it is something I do not leave the house without plus on very hot days I put a cooling vest on her which really helps plus if we going to a dog park I will make sure we sit where shade is close by so thank goodness till now I have had no problems

  5. I am sometimes guilty of not carrying enough water for Bella. We mostly hike near sources of water so I don’t pay too much attention to it. We’ve done on a couple recently, though, where we didn’t have a river or lake and I didn’t bring enough for her. I have to go look back at the images from that hike to see if I can tell a difference in her tongue color! Thanks for the great tips.

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