Kennel cough is a highly contagious respiratory infection that causes a harsh, honking cough in dogs. Most healthy dogs recover in one to two weeks with rest. In a French Bulldog, though, kennel cough deserves a quicker call to the vet, because short-nosed breeds have less breathing reserve when their airways get inflamed.

Kennel cough symptoms and sound

The classic sign is a loud, dry cough that sounds like a goose honk, often followed by retching or gagging, as if the dog is trying to bring something up. Gentle pressure on the windpipe easily sets it off,[1] so a collar pulling on a walk can trigger a coughing fit. Some dogs also sneeze or have a runny nose.[2]

Signs typically appear 2 to 10 days after exposure (about 6 days on average for Bordetella).[2] So a cough that starts a few days after daycare, a grooming appointment or a boarding stay fits the pattern.

Practical tip for Frenchies: while your dog is coughing, walk on a harness, not a collar, to keep pressure off the trachea.

How long does kennel cough last?

In most dogs, severity drops during the first 5 days, and the illness lasts 10 to 20 days in total.[1] Many mild cases clear completely within 7 to 10 days.[2][3] Stress can bring the cough back during recovery.[1]

A cough that is still going strong after two weeks, or that gets worse instead of better, needs a recheck.[3]

Why French Bulldogs need closer watching

During the wave of canine respiratory illness reported across the US in late 2023, the AVMA listed the dogs at higher risk: very young or old dogs, dogs with heart or respiratory disease, immunocompromised dogs, and short-nosed (brachycephalic) breeds such as French Bulldogs. An AVMA expert panel advised prompt veterinary care for brachycephalic dogs.[3][5] No single new germ was confirmed behind that outbreak, and the AVMA said respiratory outbreaks like it happen regularly.[3][5]

The reason for extra caution is anatomy. Many Frenchies already breathe through narrow nostrils and a long soft palate. An infection that swells the airways leaves them little margin. If your dog snores heavily or tires quickly even when healthy, read our guide to French Bulldog noisy breathing.

When kennel cough is an emergency

Kennel cough can turn into pneumonia, especially in puppies.[1] Call your vet the same day if you notice:

  • Fever, lethargy or refusing food[1]
  • Thick yellow or green nasal discharge[1]
  • A wet, productive cough[1][4]
  • Coughing so hard it causes vomiting[3]
  • A cough that lingers or worsens[3]

Go to an emergency vet now if breathing is labored or your dog is struggling to get air.[3][4]

Is kennel cough contagious?

To other dogs: very. It spreads through droplets from coughing and sneezing, direct contact, and shared objects like bowls and toys. It moves fastest where dogs are close together: daycare, boarding, shelters, groomers, dog parks and vet clinics.[1][2] Dogs can spread it while looking healthy.[3]

How long: Cornell notes that a dog can stay contagious for up to 8 weeks, possibly longer, after the cough stops, and Bordetella survives on surfaces for at least 10 days.[2] Keep your dog away from other dogs while coughing and for a while after. Clean bowls and hard surfaces with diluted bleach at 1 part bleach to 32 parts water (about 1/2 cup per gallon).[2]

To cats and people: rarely. Bordetella bronchiseptica can also make cats sick, and it has infrequently caused illness in people, typically those with weakened immune systems.[2] If someone in your home is immunocompromised, mention it to your vet and your doctor.

Kennel cough treatment at home and at the vet

Most dogs with only a cough recover at home. According to the Merck Veterinary Manual, antibiotics are usually not needed unless pneumonia is present, and a vet may prescribe a cough suppressant for a persistent dry cough (never when there is pneumonia).[1] Cornell adds that steroids and anti-inflammatories do not shorten the illness.[4]

At home:

  • Rest, with short, calm potty walks on a harness.
  • Fresh water always available and a smoke-free home.
  • Keep your Frenchie cool; heat and excitement make breathing harder.
  • No human cough syrups. Some contain ingredients that are toxic to dogs, and dosing should only come from your vet.

Kennel cough vaccine

Bordetella vaccines come as intranasal (nose drops), oral and injectable forms. The 2022 AAHA Canine Vaccination Guidelines class them as noncore, meaning they are recommended based on lifestyle and risk. The intranasal or oral version is a single dose with yearly boosters; the injectable needs 2 doses 2 to 4 weeks apart, then yearly boosters.[6] Canine influenza vaccines are also noncore.[6] WSAVA calls respiratory vaccines non-core for pet dogs in typical homes but important in shelters.[7]

Cornell recommends the vaccine for dogs that board, visit the groomer or play at dog parks, and the same logic applies to daycare. A vaccinated dog can still catch kennel cough, but it usually gets milder disease and a lower risk of pneumonia.[4] Puppies are building their whole vaccine series at the same time, so see our guides to distemper in dogs and safe puppy socialization.

Sources and references

  1. Tonozzi CC. Kennel Cough (Canine Infectious Tracheobronchitis) [Internet]. Merck Veterinary Manual; 2022 Feb [updated 2024 Sep; cited 2026 Nov 3].
  2. Cornell University College of Veterinary Medicine, Cornell Richard P. Riney Canine Health Center. Bordetellosis [Internet]. Cornell Riney Canine Health Center; [date unknown] [updated 2025 Nov 20; cited 2026 Nov 3].
  3. American Veterinary Medical Association. Answering clients' questions about CIRDC [Internet]. AVMA@Work blog; 2023 Dec 6 [cited 2026 Nov 3].
  4. Cornell University College of Veterinary Medicine, Cornell Richard P. Riney Canine Health Center. The risks of kennel cough [Internet]. Cornell Riney Canine Health Center; [date unknown] [cited 2026 Nov 3].
  5. Nolen RS. Making sense of the mystery illness found across the US [Internet]. AVMA News; 2023 Dec 5 [updated 2023 Dec 7; cited 2026 Nov 3].
  6. American Animal Hospital Association. Recommendations for core and noncore canine vaccines [Internet]. 2022 AAHA Canine Vaccination Guidelines; 2022 [cited 2026 Nov 3].
  7. WSAVA Vaccination Guidelines Group. 2024 Guidelines for the Vaccination of Dogs and Cats: Executive Summary [Internet]. WSAVA; 2024 [cited 2026 Nov 3].