Home Dog Bad Breath

Dog Bad Breath: Causes and How to Fix It

By the Dog Health Handbook team · Updated · Fact-checked against current veterinary references (see sources)

Key takeaways

  • Bad breath isn't normal. It usually means gum disease.
  • Dental disease is the most common disorder vets diagnose in dogs.
  • A sweet or urine-like smell can signal diabetes or kidney problems.
  • Daily brushing with dog toothpaste works best at home.
  • Avoid antlers and bones, which can break teeth.

Table of Contents

Research Causes Fishy breath Vet treatment Home care Puppy breath FAQ Sources

Dog General Diseases and Symptoms QuickLinks

Lyme Disease Overview Lyme Disease Symptoms Lethargic Dog Fever and Temperature Shaking and Trembling Not Eating Drooling Bad Breath Poisoning Chocolate Grapes and Raisins Xylitol

Bad breath (halitosis) isn't normal in dogs, even in older dogs.1 Most of the time it comes from the mouth. Plaque and tartar on the teeth lead to gum disease, and the bacteria involved release foul-smelling sulfur gases.2,3 Gum disease is extremely common. Most dogs have some by age 3, and dental disease is the most commonly diagnosed disorder in UK dogs.4,5 Less often, bad breath is a sign of a broken tooth, a mouth tumor, something stuck in the mouth, or a problem elsewhere in the body, such as kidney disease or diabetes.6,1,7 This guide explains the causes, the warning signs, how vets treat it, and what actually helps at home.

See your vet promptly if your dog's bad breath comes with:

  • A sweet or nail-polish-remover smell, especially with weakness or vomiting (go now: possible diabetic emergency)1,8
  • A urine or ammonia smell with more drinking or urinating1,7
  • Yellow gums or eyes, vomiting or poor appetite7
  • Drooling, pawing at the mouth, bleeding, a lump in the mouth, or not eating7,9
  • A swollen face or a broken tooth6,10

What the Research and Guidelines Say

  • Dental disease is the most commonly diagnosed disorder in UK dogs. In a UK study of more than 22,000 dogs, about 1 in 8 was diagnosed with dental disease in a year, more than ear infections or obesity.5
  • Small and older dogs are most at risk. Dogs under 10 kg (22 lb) had about 3 times the risk of dogs weighing 30 to 40 kg, and dogs aged 12 or older had nearly 4 times the risk of dogs aged 2 to 4. Toy Poodles had about 4 times the risk of crossbreeds.11
  • Brushing frequency matters. In a study of beagles, brushing more often gave better control of plaque, tartar and gum inflammation.12
  • Hard chews break teeth. Studies report broken teeth in about 20 to 27% of dogs, and a veterinary dental specialist reports that antlers are now among the most common causes of a broken upper chewing tooth.13,14

Why Does My Dog's Breath Smell So Bad?

Mouth causes (the most common)

  • Plaque, tartar and gum disease. This is the most common cause. Small and flat-faced breeds, whose teeth are crowded, are especially prone.2,1,6
  • Broken or infected teeth.6,7
  • Something stuck in the mouth, such as a stick wedged across the roof of the mouth.3,7
  • Mouth tumors, which may also cause drooling, bleeding and difficulty eating.9,15 See oral cancer in dogs.

Other causes

  • Kidney disease: breath that smells like urine or ammonia as waste products build up.1,7 See kidney disease in dogs.
  • Diabetes that has become a crisis (ketoacidosis): a sweet or acetone smell.1,8
  • Liver disease: foul breath with yellow gums, vomiting or poor appetite.7
  • Eating feces or other things dogs shouldn't eat.7,3
  • Diet: fish-based foods and treats can make breath smell fishy.1,16

Why Does My Dog's Breath Smell Like Fish?

A fishy smell on the breath can come from a dental infection or from fish-based foods, treats or fish oil supplements.16 A urine-like or "bad fish" smell can also come with kidney disease, so tell your vet if your dog is drinking more.3,1

How Vets Treat Bad Breath

Your vet will look at the teeth and gums and may suggest blood and urine tests if the mouth looks healthy.6 For gum disease, the main treatment is a professional dental cleaning under general anesthesia. This cleans above and below the gumline, includes dental X-rays, and allows infected or loose teeth to be removed.2,10,17 Dogs prone to bad breath may need dental checks twice a year.2

What about anesthesia-free cleaning? Veterinary dental specialists don't recommend it. Scraping the visible tartar off an awake dog is cosmetic, can't reach below the gumline where disease does the damage, and can give a false sense of security.18,19,17

How to Get Rid of Bad Breath in Dogs

  • Brush daily. Toothbrushing is the single most effective home care. If daily isn't possible, aim for at least every other day; the less often you brush, the less it helps. Use a dog toothpaste, never human toothpaste.17,10,20
  • Start slowly. Let your dog get used to the taste of the toothpaste, then brush a few teeth at a time with a soft brush or finger brush. Only the outer surfaces of the teeth need brushing.10 For dogs that won't accept a brush, wiping the outer surfaces with gauze at least every 2 to 3 days can remove plaque.10
  • Look for the VOHC seal. Chews, diets, water additives and other products with the Veterinary Oral Health Council seal have been shown in trials to reduce plaque or tartar.21,20 They help, but they don't replace brushing or professional cleaning.21
  • Avoid hard chews such as bones, antlers, hooves and hard nylon toys, which can break teeth. A good test: you should be able to dent the chew with a fingernail.10,22
  • Skip the home remedies. Apple cider vinegar doesn't remove plaque and its acid can harm enamel.23 There is no good evidence that coconut oil controls plaque or bad breath.24 Breath sprays and breath-freshening treats may mask the smell but don't treat the cause. Don't use human mints, gum or breath products on your dog.

Puppy Breath

Young puppies often have a distinctive sweet breath, which usually fades by about 6 months of age, when the adult teeth are in.25 Bad breath in a puppy that lasts for more than a week or two during teething, or baby teeth that stay in after the adult teeth come through, is a reason for a vet check.25,10,17

Frequently Asked Questions

Should I be worried if my dog has bad breath?

Bad breath isn't normal. It usually means gum disease, which needs a vet check. Urgent signs include a sweet or urine-like smell, vomiting or not eating.

What can I feed my dog to get rid of bad breath?

Some dental diets and chews with the VOHC seal help reduce plaque, but daily brushing works best.

What does kidney failure breath smell like in dogs?

Often like urine or ammonia. See your vet, especially if your dog is drinking more.

Why does my dog's breath still smell after cleaning his teeth?

Disease below the gumline, a broken tooth or an illness elsewhere in the body may be the cause. Ask your vet.

Which dog breeds are most prone to bad breath?

Small, toy and flat-faced breeds, such as Toy Poodles and King Charles Spaniels, are most prone to dental disease.

Ask Our Team a Question

Help Others by Sharing Your Dog Story or Question!

Have a Question, Request or Want to Share a Story that could help others? Our team will answer questions for free!

Please include information such as your dog's medical history, age, sex, breed, symptoms, diet, changes in behavior and medications. Providing pictures by uploading them below can also be of help.

We will do our best to get back to you quickly (it depends on how many questions we receive each day). If you do require an immediate response we suggest using this online dog veterinary service that is available now.

[ ? ]

Upload 1-4 Pictures or Graphics (optional)[ ? ]

 

Click here to upload more images (optional)

Author Information (optional)

To receive credit as the author, enter your information below.

(first or full name)

(e.g., City, State, Country)

Submit Your Contribution

  •  submission guidelines.


(You can preview and edit on the next page)

What Other Visitors Have Asked and Answers From Our Team

Click below to see contributions from other visitors to this page...

A Rescue Shih Tzu Who Had a Dental Cyst and Five Teeth Removed Not rated yet
Reader Question My Shih Tzu, Kisses, had a dentigerous cyst associated with an unerupted first premolar on her left jaw, along with periodontal disease. …

Click here to write your own.

Sources and further reading

This article was written and fact-checked on October 19, 2026 against current veterinary references and specialist guidelines:

  1. PDSA vets and vet nurses. Bad Breath in Dogs. PDSA Pet Health Hub, August 2024.
  2. Hunter T, DVM; Bellows J, DVM, DAVDC, ABVP. Halitosis in Dogs. VCA Animal Hospitals, last updated November 23, 2023.
  3. Partridge B. Halitosis: a breath too far. Vet Times, November 19, 2018.
  4. American Animal Hospital Association. 2019 AAHA Dental Care Guidelines for Dogs and Cats. AAHA, May 3, 2019.
  5. O’Neill DG, James H, Brodbelt DC, Church DB, Pegram C (reported by VetSurgeon). The most common health problem in dogs is dental disease (reporting: Prevalence of commonly diagnosed disorders in UK dogs under primary veterinary care, BMC Vet Res 2021). VetSurgeon.org, February 17, 2021.
  6. Gardiner J. Dog with Bad Breath. UC Davis School of Veterinary Medicine Animal Health Topics, April 11, 2019.
  7. Shugg R, MS, DVM. Bad Breath in Dogs: Causes and Treatment. PetMD, February 15, 2022.
  8. Grzyb K, DVM. Diabetic Ketoacidosis in Dogs. PetMD, April 22, 2022.
  9. Reiter AM, Dipl. Tzt., DEVDC, DAVDC. Disorders of the Mouth in Dogs. Merck Veterinary Manual (pet owner version), full review May 2018, last updated June 2026.
  10. Reiter AM, Dipl. Tzt., DEVDC, DAVDC. Dental Disorders of Dogs. Merck Veterinary Manual (pet owner version), full review May 2018, last updated October 2025.
  11. Royal Veterinary College (reporting O’Neill DG, Mitchell CJ, et al., J Small Anim Pract 2021, DOI 10.1111/jsap.13405). New RVC research gets to the root of dental disease in dogs. RVC VetCompass, August 10, 2021.
  12. BVNA Science in Shorts (summarising Harvey C, et al., J Vet Dent 32(1):16–21). Effect of frequency of brushing on plaque and calculus control in dogs. British Veterinary Nursing Association, August 23, 2022.
  13. Milella L. Exploring tooth fracture risks in canine patients. Vet Times, May 21, 2019.
  14. Lewis J, VMD, DAVDC. Advise clients ‘durable’ treats are not worth the risk of tooth fractures, tissue injuries. Veterinary Practice News, July 19, 2024.
  15. PetMD Editorial; reviewed by Coates J, DVM. Dog Mouth Cancer: Symptoms, Treatment and Life Expectancy. PetMD, reviewed August 19, 2019.
  16. Morrison BJ, DVM. Why Do Dogs Smell Like Fish? PetMD, October 26, 2023.
  17. American Veterinary Medical Association. Pet Dental Care. AVMA, undated.
  18. American Veterinary Dental College. Companion Animal Dental Scaling Without Anesthesia (position statement). AVDC, adopted April 10, 2004.
  19. American Veterinary Dental College. Reasons not to Choose Anesthesia Free Dentals for Your Pet. AVDC, July 27, 2014 (modified February 3, 2016).
  20. Hart H, DVM. What Is VOHC? Understanding the Veterinary Oral Health Council and What They Do. PetMD, May 30, 2025.
  21. Veterinary Oral Health Council. VOHC home page. VOHC, accessed October 2026.
  22. Pickett L, VMD. Antlers and Other Hard Chews Break Dogs’ Teeth. Creators Syndicate (Ask the Vet), June 16, 2022.
  23. Sutton C; reviewed by Charles A, BVSc MRCVS. Apple Cider Vinegar for Dogs. Dogster, updated September 9, 2026.
  24. Aldrich G, PhD. Coconut oil: Does it belong in commercial petfoods? Petfood Industry, February 11, 2014.
  25. Crane B; reviewed by Charles A, BVSc MRCVS. What Causes Puppy Breath? Dogster, June 17, 2026.

About this article

Last updated : new page, written using Merck Veterinary Manual, AVDC, AVMA, AAHA, VCA, PDSA and UC Davis guidance and VetCompass research on dental disease in dogs.

This page is for general information and is not a substitute for an exam by your veterinarian.