Halitosis in Dogs

Plaque Halitosis is an offensive odor coming from the oral cavity.

What causes halitosis in dogs?

Halitosis is caused by:

  • bacteria associated with plaque,
  • calculus or tartar,
  • decomposing food particles retained within periodontal pockets,
  • persistent bleeding due to coagulation abnormalities, and
  • tissue necrosis.

Contrary to common belief, neither normal lung air nor stomach aroma contribute to halitosis.

The most common cause of halitosis in the dog is periodontal disease from plaque (biofilm). Bacteria are attracted to the acellular biofilm on tooth surfaces which are formed from the precipitation of salivary glycoproteins (the pellicle). Biofilm forms over a freshly cleaned and polished tooth as soon as the patient starts to salivate; the bacteria attach to the pellicle within 6-8 hours. Within days, the plaque becomes mineralized, producing rough tartar or calculus which accumulates more plaque and causes inflammation of the marginal gingivia. As plaque ages and gingivitis progresses into periodontitis (tooth support loss), the bacterial flora changes from “good” bacteria to destructive bacteria. 

The primary cause of  bad breath in dogs is bad bacteria causing putrefaction that generates smelly sulfur compounds.

Volatile sulfur compounds may also play a role in periodontal disease affecting the integrity of the tissue barrier, allowing endotoxins to produce periodontal destruction, endotoxemia, and bacteremia.

Small and flat-faced breeds are more prone to oral disease because the teeth are closer together, smaller animals live longer, and their owners tend to feed them softer food.

3 How is halitosis treated?

Treatment of halitosis in the dog involves eliminating the cause(s). First, the teeth need to be thoroughly cleaned and polished under general anesthesia. Cleaning removes plaque and calculus above and below the gum line (with the help of hand instruments and scaler tips designed to be used under the gum line).    

4After teeth cleaning, a tooth-by-tooth examination for periodontal support loss is conducted. Intraoral dental x-rays are inspected to complete the oral assessment. Often, those teeth affected by advanced periodontal disease need to be extracted.

In dogs where periodontal pockets are consistent with stage 2 and 3 periodontal disease,  and/or when bleeding is foundon probing, local anti-microbial administration may help to reduce halitosis by decreasing bleeding and diminishing pocket depths.

How can halitosis be prevented?

Oral care products containing metal ions, especially zinc, can inhibit the formation of odor through their affinity to sulfur – zinc and hydrogen sulfide form the insoluble, zinc sulfide. Zinc also interferes with microbial proliferation and calcification of microbial deposits that can cause halitosis.

After the causes of halitosis have been identified and eliminated, daily plaque control is an essential part controlling and preventing halitosis from recurring. 

Tooth brushing at least twice a week is highly recommended. Daily use of dental wipes infused with sodium hexamethaphosphate (Dechra) can also help to decrease tartar accumulation. These wipes join chemical action with the physical.


Using products approved by the Veterinary Oral Health Council (VOHC.org) have also been shown to slow the accumulation of plaque and/or tartar and are endorsed by the American Veterinary Dental College.


This client information sheet is based on material written by: Jan Bellows, DVM, Dipl. AVDC, ABVP

© Copyright 2013 LifeLearn Inc. Used and/or modified with permission under license.