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Why Does My Dog Suddenly Have Bad Breath? 9 Reasons & Tips

Why Does My Dog Suddenly Have Bad Breath

Warning: If your dog suddenly has bad breath, it could be caused by something serious.

Read on to discover:

  • 9 reasons why your dog has bad breath all of a sudden.
  • 7 simple but doable tips to get rid of your dog’s bad breath.
  • The possible underlying diseases that lead to stinky breath.
  • Why small dog breeds are more prone to bad breath and dental diseases.
  • And many more…

Why does my dog suddenly have bad breath?

Your dog suddenly has bad breath because they ate gross things. They either foraged your garbage bins or ate long-dead animals. Or they ate their own poop or another dog’s poop. This is a condition called coprophagia. Sudden bad breath can also occur if they ate a toxic substance like antifreeze.

People also ask:

9 reasons why your dog has bad breath all of a sudden

#1: Poor oral hygiene

Dogs love giving kisses. Or getting in your face.

But what if your dog’s breath smells like a rotten fish? Getting close to them is the last thing you want.

Bad breath in dogs can come from poor oral hygiene.

It’s similar in humans, really. Don’t brush your teeth for several days. Everyone will start keeping their distance from you.

Dogs can’t brush their teeth on their own. So if you neglect to brush their teeth, there will be a build-up of plaque and tartar. These, in turn, lead to the development of bacteria that cause bad breath.

Over time, poor oral hygiene will lead to infection, pus, and cavities. All these can lead to your dog’s nasty breath.

#2: Dental and gum disease

Your dog has bad breath all of a sudden. It’s worrying because it could be a sign of something serious.

Such as a dental or gum disease.

Did you know that the incidence of dental diseases increases as dogs get older?

Let’s say your dog has plaque build-up. It pushes the gum away from the teeth. When this happens, bacteria has new areas to attack.

Plaque build-up also inflames a dog’s gum in what is called gingivitis. Try lifting your dog’s lip. You might see their gums very red and inflamed. Most often, you’ll see the plaque build-up on their teeth.

Neglected inflammation and infection can lead to periodontal disease. It will damage the ligaments of your dog’s teeth.

Also, plaque and tartar build-up can lead to tissue damage and tooth loss. Further, there might be cavities that you don’t see because they’re below the gum line.

All these can lead to your dog’s foul breath.

#3: Metabolic diseases

Some metabolic diseases can lead to bad breath. 

Let’s look at them one by one.

Kidney disease

One of the purposes of the kidneys is to eliminate waste products. But if the kidneys are unable to do this, problems arise.

For one, these waste products build up in the bloodstream. And then these manifest in the breath of the dog.

Kidney disease will leave an ammonia-like smell on your dog’s breath. If you smell pee on their breath, that’s an indication of kidney disease.

Warning: Kidney disease could lead to kidney failure. This is the last and most severe stage. Bad breath caused by kidney failure has a metallic smell. 

Liver disease

A foul-smelling breath can also be a warning sign of liver disease. The stench is accompanied by other symptoms such as vomiting and lack of appetite.

Also, check your dog’s gums. If those have a yellow tinge, it could be liver disease.


According to PetMD, diabetes leaves a sweet, fruity smell to your dog’s breath. It may not alarm you. But if you smell it on your dog’s breath, it could be diabetes.

Look for other symptoms such as excessive drinking of water and urination.

Warning: Diabetes, kidney disease, and liver disease are serious and need immediate treatment.

#4: Gross things

Dog Suddenly Has Bad Breath Ate Poo

Does your dog’s breath smell like poop? That’s probably because they ate poop!

Sometimes your dog decides that something yucky is delicious. Not only poop but garbage and rotten animal carcass as well.

You might not notice that your dog has access to your garbage bins. Or to your cat’s poop, which many dogs seem to love eating.

Or to their own poop or other dog’s poop! This is a disorder called coprophagia.

Many pet owners are left puzzled by this odd canine behavior. In this study, the authors wanted to find out why this behavior occurs.

The authors used two web-based surveys. The first one aimed to compare dogs that eat poop to dogs that do not. The other aimed to find out more information from pet owners.

The results showed that 16% of dogs engaged in coprophagia. These dogs were observed to have eaten poop at least 6 times.

The dogs’ age and diet had nothing to do with the behavior.

#5: Tumors in the mouth

If your senior dog has bad breath, it could be due to tumors in the mouth.

Aside from teeth and gums, oral tumors are a source of bad breath. These tumors grow too fast. 

Too fast that blood vessels can’t keep up. This leads to dead areas that bacteria attack.

The bacteria are what cause the foul odor.

#6: Respiratory tract diseases

If your dog’s breath smells as bad as a sewer, they need immediate help! The cause could be diseases of the respiratory tract.

These diseases include sinusitis and nasal infections.

The awful smell comes from pus. It contains dead cells and tissues, bacteria, and blood.

The pus in the nose then trickles to the back of the throat. So when your dog exhales, the breath smells bad.

#7: Teething

Puppies are supposed to have the sweetest breaths. 

But don’t worry if sometimes their breath stinks. It doesn’t last.

Their breath smells bad due to the bacteria that collects at the gum line. This is when an erupting adult tooth pushes out the baby tooth.

After this period, the bad breath should go away. If not, the bad smell could be one of the other reasons discussed in this article.

#8: Gastrointestinal diseases

Diseases of the gastrointestinal system can wreak havoc on your dog’s breath.

Especially megaesophagus. 

According to this study, this is a disorder where the muscles of the esophagus lose their tone. As a result, the esophagus is unable to send food into the stomach. Also, the esophagus becomes dilated, causing it to become dysfunctional.

In the study, five dogs of different breeds were observed. All have bad breath as a symptom of megaesophagus. Other symptoms observed were weight loss, lethargy, and dehydration.

Aside from megaesophagus, persistent vomiting due to metabolic diseases leads to bad breath.

Also, there’s an infection of the mouth or the lip folds. Some dog breeds are more prone to this, such as Spaniels.

#9: An imbalance in oral and stomach microbiome

A balanced oral and gut microbiome is important for your dog’s health.

If there’s too much bad bacteria, an imbalance occurs. And it can lead to a dog’s bad breath from the stomach.

How? Too much bacteria in the small intestine leads to smelly gas.

This smelly gas is absorbed in the bloodstream. When a dog exhales, the breath smells stinky.

But how can an imbalance in the oral microbiome lead to bad breath? Through saliva.

Saliva is a swimming pool of bacteria from the mouth. And dogs swallow a lot of saliva.

So the bacteria from the mouth end up growing in the stomach. This leads to an imbalance in the microbiome, which then leads to bad breath.

#10: The dog’s food

Unfortunately, some dog food can make your dog’s breath stinky.

A friend of mine has a dog that experienced bad breath due to wet food. There might be ingredients in the food that negatively affect a dog’s digestive system.

Hence, the foul-smelling breath.

#11: Your dog ingested a toxic substance

Some toxic substances smell very bad. 

And if a dog ingests one of them, you’ll be able to tell the difference by how their breath smells. 

Toxic substances include (but are not limited to) antifreeze and rodenticide.

Warning: If you think your dog might have ingested a toxic substance, waste no time. Call your vet and have your dog checked immediately.  

7 tips on how to get rid of your dog’s bad breath

#1: Dental cleaning

The first step to getting rid of your dog’s bad breath is determining the cause.

And that’s with the help of your vet. Thus, it helps to take note of all symptoms or odd behaviors your dog displayed. This is a huge help so the vet can narrow down the possible cause.

Besides, the symptoms can help the vet make decisions on what kind of tests to do. And so that the vet can determine the best treatment.

If there are no underlying diseases, then what your dog needs is dental cleaning. The vet will take a blood sample to make sure your dog can take anesthesia.

And depending on the damage, the vet may remove a loose or damaged tooth.

#2: Regular brushing of teeth

At home is where bad breath prevention starts. Protect your dog from bad breath and other dental diseases through regular brushing.

Just like in humans, daily brushing is the gold standard to prevent gum and dental diseases. Without these diseases, your dog will be free of bad breath.

This good boy definitely loves getting his pearly whites brushed!

Remember, it falls on your shoulders to keep your dog’s teeth clean. Daily brushing is the best start, as this study suggests.

The study had Beagles as subjects. Four brushing techniques were employed:

  • Brushing daily
  • Brushing weekly
  • Brushing every other day
  • Brushing every other week

The study lasted 28 days.

After this period, the dogs’ teeth were examined for plaque, calculus, and gingivitis.

The results found that brushing frequently (daily and every other day) is more optimal. Specifically, it retarded plaque and calculus build-up. Plus, it reduced the severity of gingivitis.

Another study supported the daily brushing of teeth. The researchers had 20 Beagles for subjects, divided into the following groups:

  • Group 1 – Scaling
  • Group 2 – Scaling + polishing
  • Group 3 – Scaling + tooth daily brushing
  • Group 4 – Scaling + polishing + tooth daily brushing

The study ran for 8 weeks.

After which, the number of oral bacteria was counted using a bacterial counter. Unsurprisingly, dogs in groups 3 and 4 had lower numbers of bacteria compared to the other groups.

The authors suggested daily brushing of teeth to stop or prevent bacterial growth.

#3: Give small dog breeds special dental attention

According to the American Kennel Club (AKC), small dog breeds are more prone to dental diseases.

That’s because of their tiny teeth that are placed close together. As it turns out, this promotes plaque build-up.

Thus, from a young age, they need to have their teeth brushed regularly. And they need chew toys to help keep their choppers clean.

#4: Clean surroundings

A nice, clean place helps prevent your dog from going after gross things.

This means securing the lid of all your garbage bins. 

Also, watch out when you’re walking your dog outside. They could easily rummage through the neighbor’s garbage bins. Or run after roadkill.

At home, keep your cat’s litter box out of your dog’s reach. 

If you have multiple animals and they all poop outside, clean up after them immediately. This prevents any incidences of your dog going after the poop.

#5: Healthy options for home remedies

Aside from chew toys, there’s a dog’s bad breath home remedy you can give.

Carrots and apples

Carrot and apple slices are a healthy home remedy for bad breath. These keep your dog’s breath smelling fresh.

Plus, munching on these can help prevent plaque and tartar build-up.

This Lab surely enjoys munching on a carrot:

Carrot and apple slices are also good for teething puppies.

Coconut oil

The good thing about coconut oil is its immunity-boosting powers. It can do wonders to your dog’s skin and coat.

It’s also useful for combating canine bad breath. Just add a bit to your dog’s food.

Caution: Use just a bit at a time to prevent stomach upset.


Munching on celery stimulates the production of saliva in the mouth. And saliva is important to wash away some accumulated bacteria in the mouth.

Also, celery can act as floss for the teeth. It is also low in starch but high in moisture, making it a healthy option to keep your dog’s breath fresh.

Here’s a French Bulldog eating a stick of celery with his paws!

Apple cider vinegar

Apple cider vinegar is another home remedy for bad breath. Just add half a teaspoon to your dog’s water bowl.


Parsley is not just for garnishing. It’s full of vitamins and minerals for immunity and kidney health. 

It also contains antioxidants to help treat digestive problems. And, it’s a breath freshener.

You can add a bit of parsley to your dog’s food. Or blend it with water to create a juice.

Warning: Use the curly leaf variety as this is healthy for your pet. Avoid the spring parsley, a member of the carrot family. Spring parsley is toxic to dogs.

#6: Plenty of dental chews

Fix Sudden Dog Breath With Dental Chews

You might have asked yourself, What can I give my dog for bad breath?

Aside from regular brushing, provide your pooch with lots of dental chews. These chews not only keep your dog’s teeth and jaws strong.

According to this study, a dog can benefit so much from daily dental chews. The author observed 60 adult dogs for a period of 28 days.

The dogs were divided into 2 groups. The test group consisting of 30 dogs, was given a dry diet and one dental chew daily. 

The control group with 30 dogs had a dry diet only.

The dental chew had a knucklebone shape on one end and a toothbrush shape on the other.

The author measured the oral care benefits of dental chew to:

  • Bad breath
  • Gingival indices
  • Plaque and calculus control

After the 28-day period, the author found out that a dental chew had significant effects. In particular, it reduced plaque and calculus accumulation. Bad breath was also reduced.

There are many types of dental chews you can give your dog. Here are some:

Dental diets

Some dog foods have formulations that help reduce plaque. Also, some kibbles have textures that create a scrubbing action.

Other dog foods are made with a special coating to prevent bacteria.

Note: Consult with your vet regarding the best choice for your pooch.

Rawhide chews

These are made from hides of either cows or horses. They help reduce tartar and plaque.

Chew toys

Chew toys are beneficial for all dogs. But especially for ones that can eat an edible chew too fast.

Note: Aside from the dental benefits of chewing, it’s also an entertaining activity for your dog. So they’re happy, busy and healthy at the same time.

#7: Treatment for your dog’s disease or illness

If the cause of your dog’s bad breath is an illness or disease, it must be treated first. 

Get your vet’s treatment plan for your dog’s diabetes, liver, or kidney disease. The vet can also prescribe the best treatments for oral tumors and other diseases.

Once the disease is cured, the bad breath will go away.