Bad Breath: Common Causes and What Actually Helps

Bad breath, or halitosis, is common and usually fixable. Most of the time it starts in the mouth itself, which means the solution is often a better cleaning routine or a visit to the dentist. Occasionally it is a clue to something else going on in the body. This guide covers the common causes described by the ADA and MedlinePlus, what helps, and when to get checked.

Where bad breath comes from

MedlinePlus says bad breath is usually related to poor dental hygiene: when you don’t brush and floss regularly, bacteria in the mouth release sulfur compounds (MedlinePlus: Breath odor). The ADA’s MouthHealthy site explains that hundreds of types of bacteria naturally live in the mouth, feed on leftover food, and leave a foul-smelling waste product behind (MouthHealthy: Bad breath).

Common causes

Bacteria and plaque

Food left between teeth, along the gumline and on the tongue gives bacteria a steady supply. This is the most frequent cause and the easiest to address.

Dry mouth

MouthHealthy explains that saliva works around the clock to wash out the mouth, so when you don’t make enough, the mouth isn’t cleaned as well. It lists certain medications, salivary gland problems and mouth breathing as causes. “Morning breath” is partly due to lower saliva during sleep. Our guide to dry mouth covers causes and remedies.

Gum disease

MouthHealthy says bad breath that won’t go away, or a constant bad taste, can be a warning sign of advanced gum disease. NIDCR lists persistent bad breath among the symptoms of gum disease (NIDCR: Gum disease). See our gum disease signs guide.

Food and drink

Garlic, onions and coffee are familiar culprits. MedlinePlus also lists cabbage. These odors fade once the food is digested, but brushing only masks them temporarily.

Tobacco

MouthHealthy says smoking causes bad breath, irritates the gums and dulls the sense of smell, so smokers may not notice their own breath. Our guide to smoking, vaping and oral health explains more.

Dental problems

MedlinePlus lists cavities, an abscessed tooth, an impacted tooth and dentures among possible causes. A tooth infection can produce a bad taste as well as odor; our guides to cavities and tooth abscesses explain warning signs.

Nose, throat and other medical causes

MedlinePlus lists sinus and throat infections, tonsils with deep crypts, and reflux (GERD) among causes, along with more serious conditions. It notes that some disorders cause distinctive breath odors: a fruity odor can be a sign of ketoacidosis in people with diabetes, which can be life-threatening, and an ammonia-like odor can occur with chronic kidney failure. MouthHealthy says that if your dentist has ruled out mouth causes and you brush and floss daily, your bad breath could be from another problem such as a sinus condition, reflux, diabetes, or liver or kidney disease, and you should see your healthcare provider.

What helps

Clean thoroughly every day

MouthHealthy recommends brushing twice a day and cleaning between your teeth daily to remove the bacteria that cause bad breath. Pay attention to the gumline and the back teeth, where food collects.

Clean your tongue

The back of the tongue can hold a coating of bacteria. Gently brushing it or using a tongue scraper is a simple step many people skip. MedlinePlus includes proper dental hygiene, especially flossing, in its home care advice.

Use mouthwash wisely

MouthHealthy notes that over-the-counter mouthwashes can help kill bacteria or neutralize and temporarily mask bad breath. They are a supplement to brushing and cleaning between teeth, not a replacement, and won’t fix an underlying cause like gum disease.

Keep your mouth moist

Drink water through the day. If a medicine seems to dry your mouth, ask your doctor or pharmacist whether there is an alternative, and don’t stop a prescribed medicine on your own.

Clean dentures and appliances

Dentures, retainers and night guards can collect bacteria. Clean them daily as instructed by your dentist. Our retainer care guide includes cleaning tips.

See your dentist

Regular checkups and cleanings remove hardened plaque you can’t brush away and catch gum disease and decay early. Our guide on how often to see the dentist explains how visit frequency is decided.

When to get checked

• Bad breath persists even with good daily cleaning.
• Your gums bleed, are swollen, or are pulling away from your teeth.
• You have tooth pain, swelling or a bad taste that won’t go away.
• You notice a fruity or unusual odor, especially if you have diabetes. MedlinePlus describes this as potentially serious.
• You also have sinus symptoms, heartburn, or other new health problems.

A simple daily routine

1. Morning: brush thoroughly, including along the gumline, and gently clean your tongue.
2. During the day: drink water, especially if your mouth feels dry, and rinse with water after strong-smelling foods if you can’t brush.
3. Evening: clean between your teeth with floss or another interdental cleaner, then brush.
4. Appliances: clean dentures, retainers or night guards as directed and store them properly.

If you follow a routine like this for a couple of weeks and the problem continues, that is useful information for your dentist. It suggests the cause may be gum disease, a dental problem, or something outside the mouth.

Bad breath and children

Children can have bad breath for many of the same reasons adults do, including plaque, mouth breathing and dry mouth. MedlinePlus also notes that an object stuck in the nose, which usually happens in children, can cause bad breath, often with discharge from one nostril. If your child has persistent bad breath, ask their dentist or pediatrician.

What your dentist will check

At a visit for bad breath, your dentist will usually look for plaque and tartar buildup, check your gums for signs of disease, look for cavities, cracked fillings or infection, and examine your tongue and any dentures or appliances. They may ask about medicines, dry mouth, sinus or stomach symptoms, and tobacco use. If the mouth looks healthy, they may suggest you see your doctor to look for other causes.

Frequently asked questions

Why do I have bad breath even though I brush?

Brushing may miss the tongue and the spaces between teeth. Dry mouth, gum disease, tobacco, food and some medical conditions can also play a role. If it persists, see your dentist.

Does mouthwash cure bad breath?

MouthHealthy says mouthwash can kill bacteria or temporarily mask odor, but it doesn’t treat underlying causes.

Can bad breath be a sign of a health problem?

Sometimes. MedlinePlus lists conditions including diabetes, reflux, sinus infections and kidney disease that can affect breath.

How can I tell if I have bad breath?

It can be hard to judge your own breath, especially if you smoke. Ask someone you trust, or ask your dentist at your next visit.

Is morning breath normal?

It is common. Saliva flow drops during sleep, which lets bacteria build up. Brushing and cleaning your tongue in the morning usually helps.

Sources

• MouthHealthy (ADA): Bad breath
• MedlinePlus: Breath odor
• MouthHealthy (ADA): Smoking
• NIDCR: Gum disease

By the Dentist Review Editorial Team.

This article is for general information only and is not medical advice. Talk to a licensed dentist about your own situation. See our disclaimer.

Featured image: “Tongue Scraper” by Niro5 at English Wikipedia, via Wikimedia Commons, public domain (see file page). Resized and compressed for the web.