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Healthy Tips

Surprising Causes of Bad Breath

Beyond Brushing

You may be walking around with it and not know. Your friends may be afraid to tell you. You may belong to the more than 50 percent of the general population that has halitosis, or bad breath.

“Bad breath is caused by bacteria in the mouth, which is why it typically arises from poor oral hygiene,” says Lea Q. Lisowski, MD. “However, in some instances, it can be caused by underlying medical conditions or lifestyle choices, ranging from a virus to the ketogenic diet.”

Here are five surprising causes of bad breath.

Tonsil Stones

“Your tonsils are on the frontline of fighting infection,” says Dr. Lisowski. “If you’ve ever had an infection or virus, you’ve maybe also noticed swelling in your tonsils.” Your tonsils detect bacteria and viruses and can engorge with white blood cells and antibodies to help fight foreign bodies. Food and drink must also go past your tonsils and can sometimes calcify into them, resulting in tonsil stones. These can cause bad breath. Some people are more prone to tonsil stones than others. You may be able to remove tonsil stones with a cotton swab, but if they become problematic, see an ear, nose and throat specialist.

Sinusitis and Postnasal Drip

Always clearing your throat? That could be a sign of postnasal drip, which is an excessive secretion of mucus from your sinuses that could be contributing to bad breath. Sinusitis, or inflammation of the sinuses caused by bacteria or a virus, can cause postnasal drip and bad breath as well.

Food and Drink

Sure, you’ve needed a piece of gum after eating a meal that’s heavy on the garlic, but your diet and drink choices can have a longer-lasting impact on the smell of your breath. In fact, many people on the keto diet report halitosis. This is because when your body is in ketosis, burning fatty acids instead of carbohydrates for energy, you release acetone, which has a sweet, fruity odor. “Caffeine and alcohol can contribute to bad breath by reducing your saliva production,” says Dr. Lisowski. “Saliva helps kill bacteria and eliminates excess food particles in your mouth.”

Gastroesophageal Reflux Disease (GERD)

GERD occurs when the muscle ring at the base of the esophagus does not properly function, allowing the contents of the stomach to rise into the esophagus. GERD has been linked to bad breath and can be treated in a variety of ways, from lifestyle changes to medications.


Similar to the effects of caffeine and alcohol, certain medications can dry out your mouth, causing bad breath. Some medications can also alter the pH level in your mouth, creating a more favorable environment for bacteria that can cause odor.

“Bad breath is largely a lifestyle concern,” says Dr. Lisowski. “If it’s inhibiting you from living your life fully and confidently, see a physician to determine its underlying cause and your subsequent treatment options.”

Lea Q. Lisowski, MD
Lea Q. Lisowski, MD
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