How Is Bad Breath Connected to Your Dog’s Oral and Gut Health?

If your dog has bad breath, the cause is often an overgrowth of harmful bacteria, either in the mouth or in the gut. Too many harmful bacteria can create an imbalance in your dog’s oral or gut microbiome.

So what is a microbiome? It’s a community of bacteria, fungi, and other microbes that live in your dog’s body and are essential for health. The gut microbiome lives in your dog’s digestive tract and the oral microbiome has its own community of important bacteria and microbes that live in your dog’s mouth.

When the gut microbiome contains too many harmful bacteria, the smelly gas those bacteria produce gets absorbed into the bloodstream and is eventually exhaled as stinky dog breath. That’s one reason conditions related to imbalances in the gut microbiome can cause extra stinky dog breath.

How Does a Dog’s Mouth or Gut Become Imbalanced?

A microbiome is imbalanced when it’s missing “good” bacteria, contains too many harmful bacteria, or doesn’t have enough diversity. Factors like disease, age, diet, and medications—especially antibiotics—can cause bacterial imbalances in your dog’s mouth or gut.

Missing Good Bacteria

Too Many Harmful Bacteria

Not Enough Diversity

How Can You Give Your Dog Relief Right Now?

For dogs with severe or chronic bad breath caused by poor gut health, we recommend our DoggyBiome™ Gut Restore Supplement.

The supplement introduces an entire community of beneficial dog-specific bacteria to add diversity and bring balance to the gut while relieving symptoms. Gut Restore is a fecal microbiota transplant (FMT) in an oral capsule. FMT has been shown to improve a wide range of symptoms in dogs with gut microbiome imbalances. Replenishing any missing bacterial populations can often resolve symptoms quickly by restoring a healthy balance to your dog’s gut. If possible, we still recommend testing your dog’s gut microbiome with a Gut Health Test.


For occasional or mild bad breath and daily gut health support, we recommend our DoggyBiome™ S. boulardii + FOS Powder.

This probiotic and prebiotic supplement is designed to support healthy gut function by promoting the growth of beneficial bacteria. It contains the probiotic yeast Saccharomyces boulardii, which helps rebalance the gut and has anti-inflammatory properties. It also contains Fructo-oligosaccharides (FOS), a prebiotic that promotes gut health and immune function by feeding “good” gut bacteria.

For dogs with bad breath caused by gum disease or other issues in the mouth, we recommend TEEF! Drinkable Prebiotic.

This safe, human-grade supplement contains a prebiotic formula, Protektin42, that promotes good bacteria in the mouth and reduces inflammation-causing bacteria to restore balance to the oral microbiome. Some dogs may benefit from using both DoggyBiome Gut Restore Supplement and TEEF! Drinkable Prebiotic.

How Can You Know What’s Going On in Your Dog’s Oral and Gut Microbiome?

We recommend testing your dog’s oral and gut microbiome. Get 20% off when you purchase our Oral Health Test and Gut Health Test together. Use code: BADBREATHBUNDLE at checkout.

You can test your dog’s oral microbiome with our at-home DoggyBiome™ Oral Health Test.

This easy test can assess the health of your dog’s mouth, revealing any bacterial imbalances that may cause bad breath, gum disease, tooth loss, and other issues.You send us a swab of your dog’s gums, and we analyze all the bacteria in your dog’s mouth. You will receive a detailed report with actionable insights to improve your dog’s oral health. The test can also help you evaluate the effectiveness of any oral health intervention, such as tooth brushing, oral prebiotics, or dental cleanings.

Test your dog’s gut microbiome with our at-home DoggyBiome™ Gut Health Test.

Gut microbiome testing can give you a detailed understanding of what’s going on in your dog’s gut, revealing imbalances that may cause bad breath.

You send us a small poop sample from your dog, and we do the rest. Using DNA sequencing, our scientists analyze all the types of bacteria in your dog’s poop and compare them to our healthy dog reference set to determine if an imbalance is present. We then provide an interactive online report of your dog’s gut microbiome with personalized diet and supplement recommendations to help relieve symptoms and improve your dog’s digestive, oral, and overall health.

How Can You Help Prevent Stinky Dog Breath in the Future?

For daily gut health maintenance that’s also important for a healthy mouth, try our treat with “healthy” benefits, DoggyBiome™ ImmuneShield™ with EpiCor® Chews.

Our chews are specially designed to maintain a healthy immune function, reduce systemic inflammation, and support your dog’s gut health. The active ingredient, EpiCor® Fermentate, is a postbiotic formulation that has been clinically shown to increase and improve immune function. The soft, trout-flavored chews are easy to give and dog-approved for tastiness!

Health Tip


Taking care of your dog’s oral microbiome with good oral hygiene practices (like daily toothbrushing with a dog-specific toothpaste) is the first line of defense for preventing bad dog breath.

Feeding a healthy, balanced diet is the best way to manage your dog’s gut microbiome. If you’ve taken our Oral or Gut Health Test, follow the diet recommendations in your dog’s personalized report to support the growth of beneficial bacteria. Since the gut microbiome is an ever-changing ecosystem that is impacted by multiple factors, including diet and medications, we suggest re-testing your dog’s gut health annually or anytime symptoms arise. A well-balanced gut microbiome will help your dog live a healthier, happier life.

Learn More About Bad Dog Breath​

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