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Why Does My Dog Have Bad Breath?

mouthwash blog post

Bad breath in dogs is more than just a nuisance. It can be a symptom of a health problem. Read on to find out why your dogs may have bad breath or halitosis.

Chronic bad breath can be a nuisance to even the bravest pup parents. Bad oral health is the biggest contributor to canine halitosis (smelly breath) along with underlying medical conditions. Your vet can use your pup’s stinky breath as a tool to diagnose health issues early, leading to timely treatment.  

Preventive dental care options and professional routine cleaning are widely available to maintain healthy teeth for your pup. But understanding why your dog has bad breath enables you to solve the issue at the root before it escalates into something far more severe. So let’s look at why your dog may have bad breath

7 Causes of Bad Breath in Dogs

It is perfectly normal for your dog to have a bit of a smell coming from their mouth. Usually, poor oral health and medical problems like periodontal disease and kidney issues can cause stinky breath in dogs. An overgrowth of bacteria due to an improper diet could be why your dog has bad breath, or sometimes your dog could eat something smelly.

Regardless, getting up close and personal with a dog suffering from halitosis is an unpleasant experience, no matter your love for them. So if you find yourself gagging the next time your dog tries to give you kisses, it’s time to address the bad breath. Here are 7 causes of stinky breath in dogs. 

  1. Poor oral health 

    If you don’t brush your dog’s mouth regularly, plaque will build up on the teeth, eventually hardening to tartar. The film of bacteria (tartar) leads to a foul smell when it breaks down food particles trapped in your dog’s teeth. The overgrowth of bacteria can cause gingivitis, an inflammation of the gums. 

    Canine periodontal disease is a major risk associated with poor oral hygiene. You may not see any pervasive signs of this disease until it advances, as it’s a silent invader. Periodontitis bacteria accumulate and infect your pup’s oral cavities and could lead to bone and teeth loss. You will observe a terrible smell from your pup’s mouth if they have periodontitis. 

    Dogs with misaligned teeth (malocclusions) or crowded teeth are at a higher risk of dental issues. This is most common in smaller dogs, especially as they tend to eat wet or canned food that doesn’t scrape off the bacteria during chewing. Smaller breeds are also more prone to having overcrowded teeth. 

    Introducing your puppy to brushing at a young age will make them more open to it as they age. It’s best to treat dental diseases like periodontitis before they advance into more severe stages. 

    The PawSafe dog mouthwash is an effective solution to helping maintain good doggy dental hygiene. This mouthwash contains an all-natural dental formula that cleans and whitens your pup’s teeth. Regular dental checkups—yearly or even bi-yearly for small breeds—ensure that your dog’s teeth remain healthy. 

  2. Improper dietary habits 

    Your dog’s breath problems may lie in what they eat. Dogs that consume a diet requiring minimal chewing, such as wet food, may have stinky breath. The act of chewing breaks down plaque buildup from the surface of the teeth leading to cleaner teeth. On the other hand, dry food encourages oral health because your pooch does plenty of chewing. 

    Fishy diets are more likely to cause bad breath in dogs. Resort to a diet rich in poultry or other animal proteins if you notice your dog’s breath getting too fishy. High carb diets and those high in sugar are some of the diets that can influence stinky breath in your pooch. 

    Dogs, unlike most mammals, don’t produce the salivary enzyme amylase. The
    enzyme is responsible for breaking down carbohydrates in the mouth before they have the chance to damage teeth. The lack of amylase in dogs means that carbohydrate molecules will remain lodged in your puppy’s teeth. 

    On the yuckier side of things is that many dogs are indiscriminate eaters and will eat all sorts of nasty things, including poop. Dogs seem to love cat poop universally, so you may catch them sneaking to the kitty’s litter box. The scientific term for this poop-eating habit is coprophagia and you may smell it on your dog’s breath. 

    It is undeniable that dogs can be gross creatures seeing as they can eat their poop. Cleaning after your dog or placing the litter box away from your pup’s reach will discourage them from eating poop. We’ve discussed other solutions for bad breath in dogs to help you deal with stinky dog breath. 

  3. Kidney disease

    Kidney problems result in the failure or difficulty of the kidneys to expel toxins and wastes from the body. You will notice bad breath in your dog If wastes accumulate in the bloodstream. A stench of pee in the mouth doesn’t mean your pup drank urine; it could indicate an inability to expel built-up ammonia.

    Renal failure is a grave topic of discussion among pet owners. You mostly observe kidney problems when the kidneys have already undergone significant damage. In fact, your dog can lose as much as 75% of function before pet parents notice any symptoms.

    Kidney disease can either be acute or chronic. Acute kidney disease is fast onset but treatable, while chronic is much more slow-acting but fatal too. Your pup may experience acute kidney failure If they ingest toxic substances like antifreeze or certain plants, so keep these products locked away. 

  4. Liver disease

    Fetor hepaticus is the distinct musty odor indicative of liver failure that you cannot miss. With liver disease, vital metabolic processes of filtering toxins from the body fail to happen in the liver. The result is that wastes, such as sulfur substances, make their way to the lungs, which your dog exhales. 

    This awful smell occurs along with other signs such as yellowish eyes and tongue (jaundice), lethargy, decreased appetite, and vomiting. If you suspect organ failure in your dog, promptly schedule an appointment with the vet to diagnose and manage the disease while still in the early stages.

    Some dogs may also have congenital liver problems such as liver shunts that make it difficult to break down proteins. This can cause a deadly build-up of ammonia in the system.  It’s important to have breeds such as Yorkshire Terriers who are prone to liver issues screened for this as it affects their dietary needs.

  5. Diabetes

    With diabetes in dogs, cells cannot properly absorb sugar from the blood due to decreased sensitivity to insulin. When the cells become energy-deprived, they burn fat instead of blood sugar, producing ketones, a type of acid. Diabetic ketoacidosis is a serious condition that can even poison your pup’s body due to elevated acidity in the blood. 

    The result is not precisely awful breath, as with most conditions discussed. Most people report the smell due to diabetes as sweet-smelling or fruity. This smell results from an accumulation of acetone in the blood from fat metabolism. Watch out for other signs like increased thirst and urination typical in diabetic dogs. 

  6. Foreign objects stuck in the teeth

    Dogs often chew items indiscriminately, some of which get stuck in the teeth and rot if they’re organic. Chewed bones can splinter if your pup is an aggressive chewer and eats brittle poultry or cooked bones. Bone splinters can pierce the gums and get stuck in your puppy’s mouth. 

    It’s easy for your dog to contract an infection when foreign objects get stuck into the teeth. These infections lead to a foul smell because the fresh around the affected area rots if the object remains. Bone splinters lead to other severe conditions like gastrointestinal blockage and even choking. Examine your pup’s mouth for injuries if you notice a foul smell, decreased appetite, and indications of pain. 

    Despite all the yucky and foreign objects that find their way into your dog’s mouth, some people claim that dogs have clean mouths. You have probably seen some doggy parents receiving kisses from their pups in the mouth (no judgment) with the justification that dogs’ mouths are cleaner than humans. Is this claim valid? We don’t believe so!

  7. Imbalanced gut microbiome

    Dysbiosis occurs when a dog’s gut microbiome gets imbalanced because of the loss of beneficial bacteria in the gut. An intricate ecosystem of bacteria exists in your dog’s gut comprising good microbiomes that aid in digestion. An imbalance of bacteria causes digestive disorders like inflammatory bowel disease. 

    Chronic malnutrition from improperly made homemade diets can cause imbalanced gut microbiota. Your dog can be allergic to a substance you feed regularly, causing disturbed gut flora. The imbalance in gut bacteria leads to gastrointestinal problems, releasing gasses that cause bad breath. 

    Some people claim that raw diets increase the risk of harmful bacteria like salmonella or E. coli, while others swear on raw food. The critics also argue that these dangerous bacteria will interfere with oral bacteria leading to bad breath. Ultimately, raw or cooked comes down to the owner with the veterinarian’s advice. 

Final Thoughts 

Bad breath in dogs results from improper oral hygiene, medical issues like liver and kidney problems, and imbalanced gut microbiota. Failing to brush your dog’s teeth leads to plaque buildup which causes oral diseases like periodontitis. 

If the bad breath is an immediate concern, dental rinses like the PawSafe dog mouthwash get rid of odor promptly. A medical examination is crucial if you notice awful doggy breath that isn’t normal for your dog. This examination helps diagnose and treat underlying medical conditions responsible for stinky breath.


Tamsin De La Harpe


Tamsin de la Harpe has nearly two decades of experience with dogs in rescue, training, and behavior modification with fearful and aggressive dogs. She has worked closely with veterinarians and various kennels, building up extensive medical knowledge and an understanding of canine health and physiology. She also spent two years in the animal sciences as a canine nutrition researcher, focusing on longevity and holistic healthcare for our four-legged companions.

Tamsin currently keeps a busy homestead with an assortment of rescue dogs and three Bullmastiffs.

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