Henry, a Cocker Spaniel who developed halitosis.

Jenny has two Cocker Spaniels. When one of the dogs – Henry – developed halitosis recently, Jenny’s first thought was that it was her own fault. She knew that she ought to be brushing her dogs’ teeth every day, but it’s difficult to fit this into a busy schedule, especially when the dogs don’t enjoy having it done. At the back of her mind, Jenny had another worry: she had heard that animals with sinister internal disease, like cancer, sometimes developed foul-smelling breath. Whatever the cause, Jenny knew that Henry’s halitosis meant that there was something wrong, and she brought him down to the vet to be checked out.

Smell detection is one of the less well-known skills of being a vet.  An examination of an animal doesn’t just involve a physical inspection: it can also include using the sense of smell.  It’s surprisingly common for owners to bring their pet to the vet with a complaint about “the bad smell”, and it isn’t always as easy as you’d think to track down the cause.  It can sometimes literally be a case of repeatedly sniffing around the animal, up and down, backwards and forwards, seeking out the epicentre of the unpleasant aroma.

Halitosis is a classic example of the challenge. When I put Henry on the consulting table, I could immediate pick up a rich, fusty odour around his head, but where was it coming from?

I checked his ears first: Cocker Spaniels have long droopy ears that make them prone to developing infections that can produce strong smells. Henry’s ears were perfectly clean and completely scent-free: the problem was elsewhere.

I sniffed around his head, seeking a more precise focus of the smell. I opened his mouth to check his teeth. Jenny may not brush them as often as the ideal, but she does give her dogs dental chews, and Henry’s teeth were in good condition. And as I opened his mouth and peered inside, I noticed that the smell became fainter rather than stronger.  The smell seemed to be coming from outside his oral cavity.

I closed his mouth and checked around his muzzle, nose and lips: this was the area where the smell was the strongest. I examined this area closely now, and I found the cause of his problem: he had infected lip folds.

Most people don’t realise that dogs have folds around their lips, but it’s a common feature, especially of breeds such as spaniels. The lower lip has wrinkles and troughs on either side, with the floppy skin in this area folding in on itself. This doesn’t normally cause a problem, but in some dogs, traces of food can get trapped in the recesses of the skin folds, which can irritate the skin. Bacteria then move into the irritated areas, producing pus, and aggravating the irritation. This is what had happened to Henry. When I smoothed out the skin of his lower lips, opening up the skin folds, I could see pus, and the smell was stronger than ever.

Treatment was simple: twice daily wipes of the sore area, and a soothing, antibacterial ointment. Harry responded well: other cases can be more complicated, with some dogs even needing “nip and tuck” surgery to smooth out the wrinkled folds on their faces.

These days, there’s no bad odour around Harry’s head. You mightn’t call his breath “sweet-smelling”, but then, he is a dog: what do you expect?


  • It’s common for pets to be brought to the vet because of an unpleasant smell
  • There are many possible causes, including infected ears and lip folds
  • Once the focus of smell is located, the right treatment can be given

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