Why Does My Breath Smell Even After I Brush?

You brushed for the full two minutes, flossed, and rinsed. Now you’re in an elevator with a coworker, cupping a hand over your mouth, breathing out, sniffing. You can’t tell.

The tongue is the usual suspect

The American Dental Association (ADA)² says hundreds of types of bacteria live in your mouth, and they can cause bad breath at any time.

The review explains where they hide. The back of the tongue is a shelter for them, and the coating there acts as a reservoir. The bacteria give off volatile sulfur compounds, mainly hydrogen sulfide and methyl mercaptan, which the review names as chiefly responsible for odor that starts in the mouth.

In the review’s numbers, tongue scrapers cut sulfur compound levels by 40%, compared with 33% for toothbrushes.

The NHS³ advice follows from that. Brush your teeth and gums gently at least twice a day for 2 minutes. Clean your tongue once a day with a tongue scraper. Clean between your teeth with interdental brushes or floss at least once a day.

When your mouth is dry

Saliva is the mouth’s rinse cycle. The ADA² says when you don’t make enough of it, your mouth can’t clean itself properly, and that dry mouth can come from medications, salivary gland problems, or breathing through your mouth.

Medications are one of the main causes. The National Institute of Dental and Craniofacial Research (NIDCR)⁴ says hundreds of medicines can make the salivary glands produce less saliva, including some for high blood pressure, depression and bladder control. It also says dry mouth is not a normal part of aging.

Bad breath is on NIDCR’s⁴ symptom list, next to a sticky feeling in the mouth, trouble chewing or swallowing, a burning sensation, and cracked lips.

For relief, NIDCR⁴ suggests drinking plenty of water, chewing sugarless gum or sucking sugarless hard candy to get saliva flowing, avoiding caffeine, tobacco and alcohol, and running a humidifier at night. The ADA² also recommends crunchy foods like carrots and apples.

Gums, food and smoking

The ADA² names garlic, onions and coffee as foods that affect your breath. Smoking and tobacco add to it, and also stain teeth and dull your sense of taste and smell.

Gums matter too. The ADA² says persistent bad breath, or a constant bad taste, can signal advanced gum disease from plaque buildup. The NHS³ lists tooth decay and gum disease among the dental causes, along with a dry mouth and fasting.

When it comes from somewhere else

About 8% of cases start outside the mouth, according to the 2013 review, in the airways, gut, liver, kidneys, or hormone system. Tonsillitis, sinus infection and acid reflux are among the examples. The ADA’s² list adds mouth infections, diabetes, and liver or kidney disease.

So if your mouth is healthy and the smell stays, that’s a reason to look further.

You may not be able to tell

Back to the elevator. The review says people with halitosis may not know it, because they can develop a tolerance or a disturbance in their sense of smell. That makes self-checks like the cupped hand unreliable.

That’s why the ADA² recommends regular dental checkups. Your dentist is the person who can say, plainly, whether there’s something to fix. You’re in good company, too. The ADA says studies show 50% of adults have had bad breath at some point.

What helps

Beyond brushing, scraping and flossing, the NHS³ suggests sugar-free mints after strong-smelling food, and advises against hard brushing that makes your gums bleed. It also advises not rinsing with water straight after brushing. An antibacterial mouthwash or toothpaste is an option. The ADA² says over-the-counter mouthwash gives temporary relief, and that sugar-free gum helps. If you wear dentures, the ADA says to clean them nightly.

The play

Try this: give the tongue a few weeks

Scrape your tongue gently once a day with a tongue scraper, along with your usual brushing and flossing.

Chew sugar-free gum or crunchy fruit after meals to keep saliva moving.

Note if the odor eases. The NHS³ says to see a dentist if it hasn’t gone away after treating it yourself for a few weeks.

When to get checked

Don’t wait if

1. Emergency

   If you have diabetes and fruity breath comes with nausea and vomiting, trouble breathing, or drowsiness or confusion, call 911 or your local emergency number. MedlinePlus⁵ calls diabetic ketoacidosis a medical emergency.

See a dentist if any of these fit:

• Bad breath hasn’t gone away after a few weeks of treating it yourself
• Your gums are painful or bleed
• You have a toothache or loose teeth
• Your dentures don’t fit or cause problems
• You have a persistent bad taste in your mouth
• Your mouth feels dry most of the time, which NIDCR⁴ says is worth a visit to your dentist or doctor to find out why

Also tell your doctor about a fruity smell on your breath.

Next time you’re in the elevator, skip the cupped hand. Ask your dentist.