Jack Russell dog with mouth open

If your dog has bad breath it could be an underlying problem.

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Why does my dog have bad breath?

By Dr. Stephanie Holmes BVetMed BSAVA PGCertSAECC MRCVS Veterinarian

Updated on the

Bad breath is very common in dogs. Most times it's nothing to worry about, but it can also be the sign of an underlying problem or disease process.

If you notice your dog has bad breath – or halitosis to give it its scientific name – you should always mention it to the vet.

If other symptoms are apparent, such as not eating, lethargy or vomiting, then urgent veterinary advice should be sought.

My dog has bad breath

Your dog's breath may smell for many reasons. Often, as with humans, they may not have drunk enough water and be mildly dehydrated or even have eaten something that could cause the breath to smell. Certain foods will cause your dog's breath to smell different. As dogs are scavengers and may also eat unsavoury things such as poop, there could be an obvious reason for the smell.

Dental disease is the most common reason for bad breath. If your dog will safely let you look in his mouth, you may be able to see browny plaque that's built up on the teeth near the gum, or red and bleeding gums. From an early age it is important to get your dog used to having his teeth brushed with a soft tooth brush and specific dog toothpaste (as some human toothpaste ingredients can be toxic to dogs). Ideally you should brush their teeth twice daily, as you would your own. Once dental disease is established, your dog will need treatment from a veterinary surgeon. Routine brushing is important after treatment to prevent or delay further disease and the need for treatment. As always prevention is better than cure.

Occasionally a dog may eat a foreign object that could get stuck in their mouth or teeth and then rot, causing a smell. Often there will be other symptoms, such as pawing at the mouth, pain and difficulty eating.

Tumours may also grow in the mouth and occasionally these can cause smells, if they ulcerate or become infected.

Bad breath smells could also be a sign of other disease processes. Dehydration due to vomiting or diarrhoea will cause a slight smell to the breath. Airway infections will lead to smells that are noticeable when your dog breathes on you. Illness coinciding with diabetes may cause smelly breath.

Kidney failure or liver failure will give a foul smell to the breath, due to toxin build up in the body. If you suddenly notice a change in the smell of your dog’s breath or it becomes pungent, make an appointment with a vet for a check up to find the underlying cause.

My dog's breath stinks

Stinking dog breath is always abnormal and your pet should be taken to the vet for a check-up. This will include a full physical examination and sometimes further tests, including blood tests, if needed.

It is estimated that around 80% of the reason for a dog's stinking breath will be dental disease. The smell is usually due to bacteria build up and infection.

Other infections or diseases of internal organs may also lead to horribly smelly breath, so blood tests may be strongly recommended so that a correct diagnosis and treatment plan can be instigated.

The smell of puppy breath

Quite often puppies have a particular smell to their breath. Some people seem to like the “puppy breath smell”. The usual cause of the smell is due to a puppy’s diet being solely of mother's milk. The break down of lactose (the sugar in milk) leads to a sweet smelling breath. However, puppies also often eat each other’s poop and this will add to the aroma.

Treatment for a dog's bad breath

The treatment of bad breath really depends on the underlying cause. Generally speaking prevention is better than cure and, given that most cases of bad breath are due to dental disease, it is very important that oral hygiene, such as tooth brushing, are started from puppyhood.

Brushing your dog's teeth twice a day with a dog-specific toothpaste and brush should help prevent dental disease in most cases. There are some rinses and mouth washes that may also help. These must be dog-specific and used under the direction of a veterinary surgeon.

If dental disease is established, your dog will need to have a general anaesthetic, dental charting to assess any tooth and gum problems, cleaning of the teeth and occasionally X-rays and extractions, as needed. If lots of teeth need to be removed, a vet may recommend a staged procedure, where some teeth are removed under one anaesthetic, the dog is allowed time to recover, and another anaesthetic is performed to remove the remaining teeth. After a dental procedure, once the gums have healed (after about seven to ten days), tooth brushing should be started.

If there is a foreign body stuck in the mouth, an anaesthetic may also be necessary to remove it.

Tumours are also often assessed, biopsied or removed under a general anaesthetic.

Other disease processes will have specific treatments: antibiotics if a bacterial infection is found; insulin and occasionally fluids for diabetes; diet changes for kidney and liver disease.

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