- A dry mouth will very quickly lead to bad breath. Saliva contains the enzymes that are needed to break down oral bacteria; without the saliva these bacteria will flourish and cause bad odors in no time. Ensure that your dog has unlimited access to clean, fresh water at all times. Persistent dehydration or excessive water intake can be a symptom of a more serious problem, such as diabetes, so be vigilant and consult your vet if you are unsure.
- This is a gum infection that is most likely to be caused by an accumulation of dental plaque. The swelling of the gum can cause a dog to have a dry mouth, which will lead to unpleasant smelling breath. Consult a veterinarian if you suspect your dog has gingivitis. In mild cases, home tooth brushing may be sufficient to tackle the cause of the infection. In severe cases, the veterinarian may wish to perform intensive teeth cleaning and possibly remove infected gum tissue with the dog under sedation.
- Kidney disease limits the effective breakdown of toxins from food. This is a serious condition and one of the early symptoms is persistent bad breath. If your dog is exhibiting any other symptoms that are consistent with kidney disease, such as lack of appetite, excessive urination, excessive drinking, or lethargy, consult a veterinarian as soon as possible.
- Food can become lodged in-between teeth and in any dental cavities, particularly in older dogs with chipped or damaged teeth. As the food decomposes, bacteria accumulate and spread around the mouth, causing a very distinctive rotting smell. Brush the dog's teeth with a canine toothpaste or give the dog an abrasive chew toy such as rawhide to remove the offending food.
- Constipation and other digestive problems will cause particularly bad smelling breath in dogs. Fortunately, despite being the cause of particularly bad breath, digestive problems are simpler to treat than dental problems. Adding supplementary fiber to a dog's diet is often sufficient to improve digestion and make bowel movements more regular. However, persistent and extremely foul-smelling breath may be a sign of a more serious stomach condition, so always consult the vet if you are in doubt.