What Causes Bad Breath In Dogs & How To Get Rid Of It

What Causes Bad Dog Breath & How to Get Rid of It

Bad dog breath is a common condition that can make some pet parents hesitate when getting close to their dog. There are many causes of bad breath in dogs. Some are rather harmless, such as your dog just ate some cat poop, while other causes could be a sign of a serious underlying health problem.

In this article, we’ll cover the common causes of persistent stinky dog breath, prevention tips, and available treatment options. You’ll learn which dogs are more prone to having bad breath and which diseases are connected to poor oral and dental health.

Common Causes of Chronic Bad Breath

If your dog’s bad breath lasts less than a few days, there isn’t too much to be concerned about. But when your dog’s breath hasn’t freshened up after a few weeks, what vets call ‘chronic halitosis’, it’s important to figure out why. First, we’ll cover the most common underlying causes of bad-smelling breath in dogs. Later, we’ll talk about science-based ways you can treat bad breath at its source.

Gum Disease

Bad Breath in Dogs - Dog with Gum Disease

Dog with Periodontal Disease (Gum Disease)

Gum disease, also called periodontal disease, affects about 80% of dogs by the time they are three years old. It’s caused by a buildup of bacteria on your dog’s teeth, called plaque, and is the most common cause of bad breath in dogs.

A healthy dog mouth has bacteria in it, but plaque promotes the growth of ‘bad’ bacteria that produce the unpleasant odors behind bad breath. If plaque isn’t removed, it can cause irritation and inflammation of the gums (gingivitis), which is the first sign of gum disease.

When left untreated, gum disease in dogs can lead to painful infections and dental problems that can also cause bad breath. And it doesn’t stop there - gum disease is linked to health issues that are dangerous to your dog’s overall health.

Diseases or Health Conditions

Harmful bacteria can cause bad breath in dogs

There are numerous diseases and health conditions connected to bad breath; that’s why for humans, there are tests that use breath to detect the early onset of certain diseases in a non-invasive way. Of the more well known connections between disease and bad breath are diabetes, liver disease, and kidney disease. Here’s how:

  • Diabetes can cause a buildup of ketones, a byproduct from the body breaking down fat instead of glucose, resulting in breath smelling sweet, fruity or like nail polish remover. Additionally, dog diabetes can also result in high sugar levels; the increased sugar content of saliva is the best food for bad, odor-producing bacteria to thrive.
  • Liver disease can cause the breath to smell musty or like a dead animal. This is because the liver is no longer able to properly filter out toxins, so stinky sulfur compounds, such as thiols, are released into the lungs.
  • Kidney disease can result in high urea levels in the body, causing the breath to smell like urine or fish. Kidneys are also an important organ for filtering out toxins.

An Imbalanced Oral or Gut Microbiome

Disease or health conditions are linked to stinky dog breath

The microbiome is a term that is used to describe a dynamic and complex community of bacteria, viruses, fungi, and other microorganisms. In your dog, for example, they have a gut microbiome in their intestinal tract and an oral microbiome in their mouth. Both play key roles in your dog’s overall health. When there aren’t enough beneficial bacteria or too many harmful bacteria, a microbiome is considered imbalanced.

Many think the route from the mouth to the gut is a one way street, but oral health and gut health are actually quite connected. Bacterial communities in both the gut and the mouth are connected to bad breath as well.


An Imbalanced Gut Microbiome Can Cause Bad Breath

An imbalanced gut microbiome can cause bad breath because an overgrowth of bacteria in the small intestine can produce a lot of smelly gas. This gas can be absorbed into the bloodstream and eventually exhaled, causing bad breath. This suggests that some conditions related to imbalances in the gut microbiome can cause bad breath.


An Imbalanced Oral Microbiome Can Cause Bad Breath

Too many harmful bacteria, like E. coli and other pathogens that grow in anaerobic pockets, can give off an unpleasant odor. In more extreme cases, an infection of a tooth or gum tissue could also create foul smelling breath.

Oral microbiome imbalances have consequences on the gut microbiome too. An imbalanced oral microbiome can disrupt the balance of bacteria in the gut microbiome. Dogs swallow a lot of saliva, which contains bacteria from the mouth, so it’s no surprise some of those bacteria end up living in the gut. An imbalanced gut microbiome is associated with numerous health conditions, from digestive issues to immune system disorders.


Susceptibility And Other Issues

Smaller dog breeds, older dogs, and breeds with short snouts are more prone to having bad breath. If your dog fits these groups, talk with your veterinarian about what oral care practices and lifestyle modifications they recommend to protect your dog from conditions associated with bad breath.

While less common in dogs, bowel obstructions, acid reflux, indigestion, and other gastrointestinal issues can manifest as bad breath. This is because bad smells associated with digestion don’t move in the right direction in the intestinal tract. Oral tumors, abscesses, and other oral health issues can cause bad breath.  

More importantly, some bad-breath causing conditions can be exacerbated with poor oral hygiene. For example, bad bacteria that enter the bloodstream through inflamed gums can cause an infection. This can worsen canine diabetes by increasing insulin resistance and making it harder to manage blood sugar levels.


How to Prevent Stinky Dog Breath

Prevent bad breath by  brushing  dog's teeth

Protect Against Gum Disease

Periodontal disease is the most common cause of bad breath in dogs, so taking care of your dog’s dental health and oral health are your first lines of defense for preventing bad breath. Here’s what veterinarians say are the most effective ways you can do this:

  • Regularly brushing your dog’s teeth with dog toothpaste and toothbrush is the most effective way dog owners can prevent bad breath. Daily teeth cleanings protect against dental disease by removing plaque buildup around your dog’s gum line.  
  • Providing your dog with lots of chew toys is also an effective way to improve oral health because the gnawing process knocks off plaque and can increase saliva production to wash away bacteria. Talk with your veterinarian about the best dental chews and dental treats for your pooch.
  • Routinely check your dog’s teeth for signs of gum inflammation or worsening of gum health to know if you need to make changes to your dog’s oral hygiene practices. Check out this peer-reviewed study about periodontal disease in dogs. It does a great job explaining and showing the different stages of gum disease so you know what to look out for.
  • Take your dog in for an annual exam, which will include a checkup of the mouth. Schedule a dental cleaning if your veterinarian recommends it. Most gum disease actually occurs under the gums, so it’s important to have that area examined and cleaned by a professional.

Assess Your Dog’s Diet

It’s no surprise that a healthy and balanced diet is good for your dog. It can help prevent smelly dog breath too! For example, certain ingredients in your dog’s food and/or treats could be negatively impacting your dog’s digestive system, resulting in bad breath due to an imbalanced gut microbiome.


Nutrients missing from your dog’s diet can also negatively affect your dog’s oral health. For example, research shows that deficiencies in vitamin A, vitamin B2 (riboflavin), vitamin B3 (niacin), vitamin B5 (pantothenic acid), and vitamin B9 (folic acid) are associated with early signs of gum disease. Supplementing your dog’s diet with a multivitamin or more liver, fish, and bananas (a great treat!) are a great way to introduce important nutrients.


The actions of chewing hard food can knock odor-causing plaque off your dog’s teeth. Talk with your veterinarian about the best food and treat options for your dog to support their dental health.

Promote A Healthy Oral Microbiome

There are several key ways to promote a healthy oral microbiome for your dog. You can take the guesswork out of where to start with a simple oral health test kit. The test provides detailed insight into the health of your dog’s oral microbiome by identifying bacterial imbalances and identifying bacteria known to contribute to gum disease. It also offers customized recommendations about what you can do to fix imbalances and address high levels of harmful bacteria.


Prebiotic supplements are an easy way to promote your dog’s oral health. Prebiotics protect against bad breath and gum disease by feeding the beneficial bacteria in your dog’s mouth. They are easy to add to your dog’s food or water.

There are many prebiotic supplements on the market that claim to improve oral health, but few have been shown to support or improve oral health. Two exceptions are the following: The DoggyBiome Oral Cleanse Powder contains evidence-based ingredients that prevent plaque accumulation and reduce levels of harmful E. coli bacteria that can colonize the oral cavity. And the TEEF! Drinkable Prebiotic is a water additive that contains ingredients shown to benefit oral health. Both supplements can be used on their own or in combination to maximize the support of oral health in dogs.

Questions You Can Ask Your Veterinarian

  • Can you show me how I should brush my dog’s teeth at home?
  • Is the food I am feeding my dog effective at removing plaque and supporting their gut health?
  • What tests are needed to determine if my dog’s bad breath is caused by an underlying health issue?

Figure out what is really going on inside your dog's mouth.

Sold out

Determine if your dog has an imbalanced gut microbiome and how to improve it.

Sold out
Sold out

A powerful probiotic blend that helps restore oral health

If you liked this article, please consider sharing it.