Stinky Breath

My dog has extremely stinky breath. I have taken him to the vet previously to check his teeth and gums, and they found no issue. I also brush his teeth and use a special dog toothpaste to prevent tartar building up. Any ideas/suggestions on what is causing this stink and how to prevent it? I have another dog and both dogs have the exact same diet, but the second dog doesn't have smelly breath.

Hello- and its excellent that you are taking your dogs' oral hygeine seriously, even if it isn't the cause of the smell.  This will have a preventative action and benefit your dog in the long-term. Dogs can have smelly breath for other reasons- perhaps relating to strongly proteinaceous food, for example.  In some animals, smelly breath can reflect an imbalance of chemicals in the blood, such as ketones in starvation or in the case of diabetes, or possibly in some forms of liver disease.  Other times, they reflect the diet (some raw diets, some highly proteinaceous diets etc).  Anal gland disease or diarrhoea (dog licks bottom, smell transfers), yeast infection in the skin around the mouth or ears can also sometimes be to blame, although your vet would usually have picked up on this by now.  Foreign bodies in the mouth or diverticuli in the oesophagus, causing food to 'pool' in the throat or pharanx, can be a concern in some dogs. Has your vet smelled the smell?  This sounds to be a good place to start.   Wishing you all the best - and please do let us know if you get to the bottom of it.

There are a number of different possible causes of bad breath in your dog, but the most common are kidney disease, liver disease and oral health issues.