What Causes Bad Breath in Dogs & How to Deal With It

One thing is for sure: Dog breath just doesn't smell that great, ever.

"I think it's always going to have a faint waft of badness," says Angelica Dimock, DVM, and the managing shelter veterinarian at the Animal Humane Society, located in St. Paul, Minn.

But bad dog breath could also be a sign of a health issue. That's why it's important to have a good idea of what your dog's "average" breath smells like.

"It's probably what our breath would smell like if we didn't brush our teeth with mint-flavored toothpaste. That's kind of the baseline: It's not going to be roses, but it shouldn't be foul," Dimock says.

If your dog's breath does take a turn for the worse, it's likely time to call a veterinarian to identify the culprit. Here are the most common reasons your dog's breath might stink.

The biggest cause of dog bad breath is periodontal disease. The bad smell that you're detecting could be rotting teeth or gums. "If it's getting worse and worse, that would be a sign of seriousness," Dimock says.

If your dog is suffering from periodontal disease, there are other signs you should watch out for besides just bad dog breath.

"If they're not chewing on their toys anymore or not eating the hard food or taking a really long time to eat their hard food. They might take one kibble, and chew it. And then come back a few minutes later, and take another kibble and they do that throughout the day. That could be them saying, 'Ouch, like something is hurting in here,'" Dimock says.

Other signs of periodontal or gum disease include:

• Receding gums
• Lumps under the eyes or in the mouth
• Bloody saliva
• Sneezing or nasal discharge
• Avoiding touches to the head or nose

To check on the state of your dog's oral health, you can lift up your dog's lip. If all you see is brown, that's probably tartar and an indication that your dog needs a teeth cleaning from a pro.

Periodontal disease is common, but it's not the only cause of bad breath in dogs. While other diseases can also be the culprit, stinky breath can be tied to other, less serious causes as well.

"Another possibility is their diet," Dimock says. "Dogs may just have difficulty digesting their food. They might be a little burpy or gassy, and so you might get that smell." Dimock says that if your dog is having issues digesting her food, her breath might smell "meaty." But it shouldn't have that same rotting smell that's from dental disease.

If you've recently switched your dog's food, your dog might just need time to adjust to the new diet. Dimock tells us that as long as your dog's stools are normal and everything else is OK, you can just wait it out. But consider a different diet if the dog doesn't do well with the new one.

"You can always give it a couple of weeks or a month, and just see if it improves. It can take time. If they are really gassy, front end and back end, then you might need a diet switch up, and your vet would be able to make recommendations," Dimock says.

If you smell bad breath, it also could be a sign of ulcers or even a small intestine issue. With a small intestine problem, you might detect a sour odor.

If a dog has diabetes, you might pick up on a "sweet" smell. That smell is ketones or a chemical the liver produces when your dog's body lacks enough insulin to convert sugar into energy. "It would be like a really fruity smell," Dimock says.

In serious cases, dog bad breath could be a sign of oral cancer. "As cancers grow, a lot of times the local tissues are rotting away because they're getting eaten by the cancer. So [bad breath] can be a sign of that," Dimock says.

A gastrointestinal cancer could also cause the breath to smell, but if cancer is the cause it's more likely to be oral cancer.

If your dog's breath reeks, you might want to check your garbage can. After all, dogs are prone to eating just about everything. And that can include rotting food.

"Another potential cause for bad breath is that your dog is getting into something like the litter box. Dogs eat their own poop, [they might be] eating a dead animal or something else," Dimock says.

Paradoxically, your dog's breath might actually smell worse following a professional dental cleaning. But this is temporary and should dissipate quickly.

RELATED: How Much Will Having My Dog's Teeth Cleaned Cost?

"Immediately after the dental [treatment], like the night of, it might smell a little weird because we do use, just like what a human dentist uses, that polishing paste," Dimock says. "Some people will have flavored ones for dogs and some don't. So it might just be this weird chemical smell. But usually, afterward, the vast majority of people are thanking us because the smells are so much better because we got rid of the source of the smell."

As your dog ages, her breath might start to smell worse. Dimock believes there are 4 key reasons behind this potential change. 

1. Tarter: "A lot of big dogs don't need a lot of dental cleanings," Dimock says. "So they're probably now developing the tartar that small dogs have had their whole life."
2. Overcrowded teeth: Many small dogs have teeth problems due to their small mouths. The teeth become overcrowded and that causes an increase in tartar buildup.
3. Indigestion: "Their digestion might not be as good as a young dog. Things could kind of burp up," she says.
4. Less saliva: "They might not have as much saliva production," Dimock says. "Things might just be slowing down a little bit so their breath might just be stinking because of that."

Unfortunately, stinky dog breath won't be fixed long-term with minty dog treats. Just like in humans, a breath mint can only mask the smell for a few hours. After another meal or a night's rest, your pup's mouth will likely smell again.

What does work: "It's getting rid of tartar or finding the source. Don't just cover it up," she says. Here are a few things you can do to clear up that foul-smelling breath.

According to VCA Hospitals, it is ideal to brush your dog's teeth daily if you can, but three times per week minimum. However, this isn't the norm with most dogs. It's easier to train younger dogs to sit through teeth brushing, so make sure to establish the habit while they're a puppy if you can.

RELATED: Tips from a Vet on How to Brush Your Dog's Teeth At Home

While they won't eliminate the problem and can't replace brushing, dental chews can help freshen your pup's breath between brushes and help to break down extra tartar. You can even try breath mints or water additives to keep your pooch's mouth smelling clean, but Dimock says they won't address the underlying problem.

"What I've come to find out is that now you have rotting breath with mint on it, so it makes it smell even worse," Dimock says.

You can also try chew toys to help with the tartar that can build up and cause bad breath. Watch out for animal bones (as these can damage your pup's teeth and potentially cause fractures) and opt for textured toys instead. Any toy that you can't indent with your thumb is too hard.

If you've ruled out that your pooch is digging through the garbage, and the foul smell is getting worse, it's probably time to seek professional help and have a vet check your dog's teeth and health. Banfield Pet Hospital recommends that adult dogs should have their teeth professionally cleaned at least once per year.

RELATED: Signs of Tooth Decay in Dogs and How to Get Your Pup Smiling Again