Bad Breath From Postnasal Drip or a Sinus Infection: What Helps

A cold, a sinus infection or allergy season can leave a stale taste at the back of the throat and breath that seems off. Here is how the nose and throat fit in.

How often the nose is the source

At a Belgian bad-breath clinic, among 2,000 patients:¹

• 76% had a cause in the mouth, mostly a coated tongue or gum disease.¹
• About 4% had an ear, nose and throat or other non-mouth cause.¹

So the mouth is the first place to look, but the nose and throat account for a smaller share.

Postnasal drip

Postnasal drip is extra mucus running down the back of your throat, often from allergies or infections.² Symptoms include:²

• A feeling of mucus draining, frequent swallowing or throat clearing
• A cough that’s worse at night
• Bad breath

Sinusitis

Sinusitis is common after a cold or flu.³ Alongside face pain, a blocked nose and green or yellow mucus, it can cause bad breath.³ Sinus and throat infections are both on the list of causes of breath odor.⁴

What helps

1. Treat the cause. Rest, plenty of fluids and pain relief help sinusitis.³ Warm drinks like soup or tea can thin mucus during a cold.²
2. Rinse your nose with salt water. It’s advised for sinusitis and thins thick mucus.²³ See nasal rinse water safety.
3. Keep up mouth care, especially brushing your tongue, so the mouth doesn’t add to the problem. See tongue scraping.
4. Note when the cold started. If your breath goes back to normal as the infection clears, that’s your answer.

When to see a doctor

• Breath odor that doesn’t go away with no obvious cause.⁴
• Breath odor with fever, cough or face pain and nasal discharge.⁴
• Sinusitis that isn’t better after 3 weeks of self-care, or keeps coming back.³
• Urgently if you’re very unwell, or painkillers don’t help.³

If your mouth checks out, ask about tonsil stones or a nose and throat referral. See also breath that smells even after brushing.

Try: “My dentist says my mouth is healthy, but I’ve had a stale taste and bad breath since a sinus infection in the spring, and I’m always clearing my throat. Could postnasal drip be the cause?”

Is It My Breath? covers this in Chapter 8, “Stones, Throats and Tongues,” in a section called “Nose and Throat.” Its Breath Log asks you to write down the day a cold starts, so a few weeks of off breath have an obvious explanation. See the book.