Let’s face it, everyone experiences bad breath every now and again—but what exactly causes it?

The culprit in most cases of bad breath is bacteria. The bacteria that live in your mouth break down food, proteins, sugars, and even skin cells. Volatile sulfur compounds (VSCs) also begin to form, which causes the foul smell.

Here are 5 common causes of bad breath and how to eliminate odor-causing bacteria and other bad breath offenders:

1 – Bacteria on the Tongue

The tongue, especially the back that is hard to reach with your toothbrush, is the perfect breeding ground for bacteria. With its many cracks, crevices, and grooves, bacteria are able to grow and release VSCs.

It’s recommended to also use oral rinses to help clean your tongue and other hard-to-reach areas. Using a mouthwash that specifically targets bacteria will leave you with cleaner, fresher breath.

2 – Plaque Buildup

After visiting the dentist, your teeth always look the pearliest of whites. However, after a while, they begin to get a yellowish hue. That dull color is a result of plaque build-up. Plaque is a soft and sticky bacterial film that forms on the teeth and gums that can lead to the production of VSCs.

The easiest way to remove plaque from your teeth and gums is to perform regular oral health maintenance with brushing, flossing, and the use of an oral rinse twice a day.

3 – Dry Mouth

Dry mouth is exactly what it sounds like—it’s when the mouth does not have enough saliva to keep the mouth wet. Everyone can experience it every now and again as a result of being nervous, sleeping with your mouth open, or even something as simple as eating dry foods.

Chewing sugar-free gum or sucking on sugar-free lozenges can help stimulate the salivary glands, which in turn washes away the odor-causing bacteria.

4 – Offensive Foods

Vegetables, like garlic and onions, are a part of the Allium family contain highly concentrated sulfur compounds. Once crushed, they produce allicin, which is responsible for the strong aroma associated with these vegetables.


The best thing to do is floss and brush your teeth as soon as possible to remove any leftover particles from your teeth. However, your stinky breath may persist considering garlic and onions can remain in your system for up to two days.

5 – Underlying Medical Conditions

Bad breath is often a result of poor oral health or gum disease, however, it can also be caused by other underlying medical conditions such as:


  • Infections or inflammation in the nose, throat, or sinuses.

  • Foreign objects lodged in the nasal cavity—especially in children

  • Gastroesophageal reflux disease (GERD)

  • Bowel obstruction

  • Aspiration pneumonia


When you have persistent bad breath that doesn’t seem to respond to any of the above tips, you should set up an appointment with your dentist and your primary care provider to help identify the underlying cause of your bad breath so it can be effectively treated.