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    Can Postnasal Drip Contribute to Bad Breath?

Postnasal Drip Not Usually Related to Bad Breath

June 1, 2012

Dear Mayo Clinic:

I have had a case of chronic postnasal drip for many years and as a result have very bad breath. Are the two related and if so, how? What can be done to treat bad breath due to postnasal drip?


Postnasal drip usually isn't related to bad breath. Instead, bad breath most often results from the breakdown of food in your mouth, bacteria in the tissues of your mouth or tonsils, dental problems, dry mouth or, rarely, an underlying disease. It is possible that your bad breath could be a result of a sinus problem, such as an infection. But in that case, you'd likely be experiencing symptoms in addition to postnasal drip. To determine what's causing your bad breath and what can be done, your situation needs more evaluation.

Nasal tissues make mucus all the time to help moisten and clean the nasal passages. Each day your nose and sinuses produce about two cups of mucus. Most is swallowed throughout the day. The amount of mucus can be increased by a cold, influenza, allergies or irritants in the air, such as tobacco smoke. The mucus can also be thickened due to dehydration or infection.

Many people with chronic postnasal drip also report symptoms of frequent throat clearing, coughing or hoarseness and change in their voice. These are all symptoms of gastric reflux, even without obvious heartburn symptoms. Reflux causes throat irritation, leading to a sensation of increased mucus in the throat.

Postnasal drip can certainly be bothersome but typically doesn't result in bad breath because the mucus is odorless. That said, an acute sinus infection could cause bad breath, but this wouldn't last for years. Also, for postnasal drip to be the only symptom of a sinus infection is very uncommon. Typically, these infections are also accompanied by nasal congestion, facial pain and pressure, cough and a reduced sense of smell.

Another possible cause of bad breath related to sinus issues could be a chronically stuffy nose that causes a person to consistently breathe through the mouth. Mouth breathing dries out saliva, and that leads to bad breath because saliva naturally cleanses the mouth, reducing particles that may cause odor. But from your description, it doesn't sound like your postnasal drip is associated with a chronically stuffy nose, so this explanation doesn't seem to fit your situation.

Much more likely is that your bad breath is coming from something going on in your mouth. Dental issues such as poor oral hygiene, gum disease and dentures that don't fit properly can be sources of bad breath. The use of tobacco products can be part of the problem, as well. Smoking dries out the mouth and often leads to bad breath.

Tonsil stones or tonsilloliths can also cause bad breath when sulfur-producing bacteria get trapped in debris within the tonsils. These small white or yellow stones may be seen or felt within crypts or recesses in the tonsils. The tonsil stones can be dislodged by gargling with warm salt water, but for severe cases, tonsillectomy may be necessary.

Although uncommon, bad breath may sometimes be linked to an underlying medical condition. For example, diabetes, gastro-esophageal reflux disease, and some metabolic disorders can lead to bad breath.

For postnasal drip, I recommend management of reflux. This includes elevating the head of your bed at night, losing excess weight, avoiding eating before bedtime, and/or treatment with anti-reflux medication for 3 to 6 months under your doctor's guidance. In addition, drinking more water and avoiding throat clearing can reduce throat irritation. If you have tonsil stones or sinus problems beyond postnasal drip, it would be reasonable to also have a medical doctor check your nose and throat.

Treatment of your bad breath will depend on its cause. To find out more about what's causing your bad breath, a good first step would be an appointment with your dentist for a thorough check of your oral tissue and teeth.

— Erin O'Brien, M.D., Otorhinolaryngology, Mayo Clinic, Rochester, Minn.

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