Dental or Gum Disease
Bad breath (known medically as halitosis) in dogs can occur when your dog has a dental condition—from gum disease or infection to tooth decay.
“A lot of times you can lift up the dog’s lip, look at their gums, [and see that] they’re very red and inflamed,” says Dr. Jeffrey Stupine, VMD, Head Veterinarian, Wellness of the Pennsylvania SPCA. “You can see the tartar build up on the teeth.” He notes that some issues can’t be seen though, including cavities below the gum line.
Although your vet looks for obvious signs of dental disease during your dog’s annual checkup, it’s a good idea to make an appointment in between visits if you suspect a dental issue.