Every dog owner carries an unconditional love for their pet. But some things can stretch that love to the limit, including bad breath. We all know that warm, fuggy smell when a panting canine friend gets a little too close for comfort. But what is normal and when should you consider there may be something more than just ‘doggy breath’ going on?

A mild, fairly non-offensive odour is a fairly typical product of most dogs’ mouths. However, if the smell changes, is highly pungent or if your pet is showing any other signs of being unwell, then it’s best to get it checked out. There are many causes of abnormal bad breath (otherwise known as halitosis) that your vet will look for during an examination. And some will come with symptoms that you can look out for at home. 

Dental disease

This is probably the most common reason for a dog to have bad breath. Imagine if we didn’t clean our teeth for a few days, weeks or even months, how smelly our breath would likely become. The same is true for dogs. By not brushing the teeth, plaque is left to harden into tartar which is a perfect breeding ground for bacteria; potentially leading to inflammation and infection of the soft tissues surrounding the teeth. This can all cause quite a stench. It is also uncomfortable for the dog and could lead to tooth loss. 

The best way to help to minimise the risk of dental disease developing is to actually brush your dog’s teeth every day. Make sure to use a veterinary toothpaste and start slowly. First by using the tip of your finger, then moving onto a finger-brush or soft-bristled toothbrush. Your vet will be able to assess your dog’s teeth to determine if they need any dental work or professional cleaning done first. Then the nursing team can show you how to keep the teeth shiny and white.


Any abnormal growth in the mouth can be a source of odour, either due to the mass itself or because it provides a location for bacteria, and therefore infection to develop. 

  • Benign growths on the gum, known as epulides (or more properly, peripheral odontogenic fibromas), are common in many breeds, especially Boxers, although they are usually nothing to worry about in themselves, it’s easy for food to get trapped in and around them and start to cause problems.
  • Tumours can grow almost anywhere and sadly, the mouth is no exception. Some types of tumour can ulcerate or even become necrotic and secondary infections are common.
  • Abscesses can form in the mouth after an injury or infection of the tissues. By their very nature, abscess are notoriously smelly, especially if they burst, and they can also be very painful. 


Probably the most common wound we would see in the mouth of dogs is that caused by sticks. Sticks will easily splinter and the resulting fragments can be painfully sharp and cause nasty injuries. If not treated, these wounds will often become infected. To minimise the risk of any oral wounds, it’s important to never throw sticks for dogs. And discourage them from chewing on them. Any sharp object obviously has the potential to cause damage if the dog chews on it. But also beware of electrical cables which can burn the mouth. And products such as caustic soda which can cause chemical burns. 

Foreign bodies

Oral foreign bodies can include large food fragments, pieces of sticks, bones or parts of a toy. Most of the time, the dog will be in understandable distress and the foreign body can be removed promptly. But occasionally they go undetected; often wedged between teeth or across the roof of the mouth. Over time, infection can set in and can cause real damage to the soft tissues structures. 

Lip fold dermatitis

This is a condition most often seen in spaniels but can occur in any breed. It is caused by the natural skin folds of the lower lip and chin becoming warm and moist which can lead to a proliferation of bacteria or yeasts causing red, sore skin and a resultant smell. Gently wiping the chin and skin folds after eating or bathing can help but if a dermatitis develops, always get it checked by a vet as in some cases medicated creams or wipes, or even antibiotics may be needed.

Stomach problems

The mouth and the stomach are connected by one tube – the oesophagus – so often if there is a problem in the stomach, you may detect bad breath. This could be because of:

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  • Gastrointestinal upset – any stomach upset that causes an increase in the amount of stomach acid produced, or triggers vomiting, could result in bad breath. 
  • Helicobacter – this is a type of bacteria found quite happily in most normal dogs. In humans, it has been associated with gastric ulcers and subsequent bad breath due to production of urea – although this link is currently unproven in animals. 
  • Diet – if a particular diet doesn’t suit your dog, it could cause excess gas to be produced. Whilst most dog owners are familiar with the results of their dog’s intestinal gas expulsion, burping as a result of excess stomach gas can also be fairly smelly. Some foods can also alter the bacterial flora of the mouth and any resulting imbalance could lead to bad breath. 

Anal glands

Yes, anal glands are at the opposite end of the body to the mouth, but they can be a cause of bad breath. If a dog’s anal glands get full or infected, they will become uncomfortable for the dog. This means they will tend to lick at them or their rear-end more than usual thus transferring that typical ‘fishy’ smell, to their front end…

Systemic disease

Sadly sometimes a simple case of ‘bad breath’ can be a sign of a much more serious condition. Animals in kidney failure will have an excess of urea within their system which can sometimes be detected on the breath. Similarly, diabetic animals can carry a sweet smell on their breath, which although isn’t an offensive smell, can be a warning sign to those that can smell it. 

Putting up with doggy breath is part and parcel of owning a dog but if you feel there may be something more going on, book an appointment to see your vet. The sooner a problem is detected, the sooner it can be dealt with so hopefully your pet can return to full lick-able health. 

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