Bad Breath in Dogs: Causes, Treatment and How to Prevent Dental Disease
Quick answer: The most common cause of bad breath in dogs is dental disease: plaque and tartar build up on the teeth, bacteria multiply, and the gums become inflamed. Other causes include something your dog ate, a foreign object in the mouth, or, less often, problems such as kidney disease, diabetes or liver disease. Daily tooth brushing, dental chews and regular vet dental checks prevent most cases. Sudden or very strong bad breath needs a vet visit.
What Causes Bad Breath in Dogs?
| Cause | What you might notice |
|---|---|
| Plaque, tartar and gum disease | Yellow-brown tartar, red or bleeding gums, loose teeth |
| Food, treats or scavenging | Short-lived smell after eating, eating feces or garbage |
| Something stuck in the mouth | Pawing at the mouth, drooling, chewing on one side |
| Kidney problems | Breath that smells like ammonia or urine, increased thirst |
| Diabetes | Sweet or fruity breath, drinking and urinating more |
| Liver problems | Very foul breath with vomiting, yellow gums or eyes |
The last three are less common but serious. See your vet promptly if bad breath comes with any of those signs.
Dental Disease: The Number One Cause
Dental disease is one of the most common health problems in dogs, and many show signs of it by age 3. Plaque hardens into tartar within days, pushes under the gumline, and can lead to pain, infection and tooth loss. Small breeds are especially prone. Warning signs:
- Persistent bad breath
- Yellow or brown tartar on the teeth
- Red, swollen or bleeding gums
- Dropping food, chewing on one side or reduced appetite
- Pawing at the face or drooling
How to Treat Bad Breath in Dogs
- See your vet to find the cause. If tartar has built up, your vet may recommend a professional dental cleaning, usually under anesthesia, which cleans above and below the gumline.
- Treat any underlying illness your vet finds.
- Start a home dental routine once the mouth is healthy (below).
How to Prevent Bad Breath and Dental Disease
- Brush daily, or at least 3 times a week, with a pet toothbrush and pet toothpaste. Never use human toothpaste, which can contain xylitol, a sweetener toxic to dogs. Follow our step-by-step guide to brushing your dog’s teeth.
- Use dental chews and toys, ideally ones with the Veterinary Oral Health Council (VOHC) seal. Avoid very hard chews such as bones and antlers, which can break teeth.
- Ask about dental diets or water additives as extras, not replacements for brushing.
- Book yearly vet dental checks, or more often for small breeds.
- Stop scavenging: keep trash secured and clean up the yard.
- Add teeth brushing to grooms. Ask your Groomit groomer to brush your dog’s teeth at each appointment as a helpful extra between home sessions.
Bad Breath in Dogs FAQs
Why does my dog’s breath smell so bad?
Most often because of plaque, tartar and gum disease. Diet, scavenging and, less often, kidney, liver or blood sugar problems can also cause it.
When should I worry about my dog’s bad breath?
If it’s sudden, very strong, or comes with drooling, not eating, vomiting, increased thirst or yellow gums, see your vet.
Do dental chews fix bad breath?
They can help reduce plaque, but they don’t replace brushing or treat existing tartar or gum disease.
Can a groomer clean my dog’s teeth?
A groomer can brush your dog’s teeth to remove surface plaque, but only a vet can remove tartar below the gumline and treat dental disease.
This article is for general information and is not veterinary advice.

