There are many reasons why you might have bad breath. You can get it if you don't brush and floss regularly. Bacteria that build up in your mouth and between your teeth produce the bad odor. Other problems in your mouth, such as gum disease, dry mouth, or cavities, may also cause it. Sinusitis or problems with your nose may be to blame. You can also have bad breath if you eat some foods, like raw onions, garlic, or cabbage. And of course smoking causes its own bad smell. Some diseases and medicines can cause a specific breath odor.

Having good dental habits, like brushing and flossing regularly, help fight bad breath. Mouthwashes, mints or chewing gum may make your breath fresher. If you have a disease that causes the bad breath, treating the disease may help give you fresher breath.

An offensive, foul breath odor resulting from a variety of causes such as poor oral hygiene, dental or oral infections, or the ingestion of certain foods.

As noted earlier, normal oral microbiota can cause dental and periodontal infections. However, there are number of other infections that can manifest in the oral cavity when other microbes are present.

Herpetic Gingivostomatitis

As described in Viral Infections of the Skin and Eyes, infections by herpes simplex virus type 1 (HSV-1) frequently manifest as oral herpes, also called acute herpes labialis and characterized by cold sores on the lips, mouth, or gums. HSV-1 can also cause acute herpetic gingivostomatitis, a condition that results in ulcers of the mucous membranes inside the mouth (Figure). Herpetic gingivostomatitis is normally self-limiting except in immunocompromised patients. Like oral herpes, the infection is generally diagnosed through clinical examination, but cultures or biopsies may be obtained if other signs or symptoms suggest the possibility of a different causative agent. If treatment is needed, mouthwashes or antiviral medications such as acyclovir, famciclovir, or valacyclovir may be used.

(a) This cold sore is caused by infection with herpes simplex virus type 1 (HSV-1). (b) HSV-1 can also cause acute herpetic gingivostomatitis. (credit b: modification of work by Klaus D. Peter)

Oral Thrush

The yeast Candida is part of the normal human microbiota, but overgrowths, especially of Candida albicans, can lead to infections in several parts of the body. When Candida infection develops in the oral cavity, it is called oral thrush. Oral thrush is most common in infants because they do not yet have well developed immune systems and have not acquired the robust normal microbiota that keeps Candida in check in adults. Oral thrush is also common in immunodeficient patients and is a common infection in patients with AIDS.

Oral thrush is characterized by the appearance of white patches and pseudomembranes in the mouth (Figure) and can be associated with bleeding. The infection may be treated topically with nystatin or clotrimazole oral suspensions, although systemic treatment is sometimes needed. In serious cases, systemic azoles such as fluconazole or itraconazole (for strains resistant to fluconazole), may be used. Amphotericin B can also be used if the infection is severe or if the Candida species is azole-resistant.

Overgrowth of Candida in the mouth is called thrush. It often appears as white patches. (credit: modification of work by Centers for Disease Control and Prevention)

Mumps

The viral disease mumps is an infection of the parotid glands, the largest of the three pairs of salivary glands (Figure). The causative agent is mumps virus (MuV), a paramyxovirus with an envelope that has hemagglutinin and neuraminidase spikes. A fusion protein located on the surface of the envelope helps to fuse the viral envelope to the host cell plasma membrane.

Mumps virus is transmitted through respiratory droplets or through contact with contaminated saliva, making it quite contagious so that it can lead easily to epidemics. It causes fever, muscle pain, headache, pain with chewing, loss of appetite, fatigue, and weakness. There is swelling of the salivary glands and associated pain (Figure). The virus can enter the bloodstream (viremia), allowing it to spread to the organs and the central nervous system. The infection ranges from subclinical cases to cases with serious complications, such as encephalitis, meningitis, and deafness. Inflammation of the pancreas, testes, ovaries, and breasts may also occur and cause permanent damage to those organs; despite these complications, a mumps infection rarely cause sterility.

Mumps can be recognized based on clinical signs and symptoms, and a diagnosis can be confirmed with laboratory testing. The virus can be identified using culture or molecular techniques such as RT-PCR. Serologic tests are also available, especially enzyme immunoassays that detect antibodies. There is no specific treatment for mumps, so supportive therapies are used. The most effective way to avoid infection is through vaccination. Although mumps used to be a common childhood disease, it is now rare in the United States due to vaccination with the measles, mumps, and rubella (MMR) vaccine.

This child shows the characteristic parotid swelling associated with mumps. (credit: modification of work by Centers for Disease Control and Prevention)

Periodontal disease is the result of infections that lead to inflammation and tissue damage in the structures surrounding the teeth. The progression from mild to severe periodontal disease is generally reversible and preventable with good oral hygiene.

Gingivitis

Inflammation of the gums that can lead to irritation and bleeding is called gingivitis. When plaque accumulates on the teeth, bacteria colonize the gingival space. As this space becomes increasingly blocked, the environment becomes anaerobic. This allows a wide variety of microbes to colonize, including Porphyromonas, Streptococcus, and Actinomyces. The bacterial products, which include lipopolysaccharide (LPS), proteases, lipoteichoic acids, and others, cause inflammation and gum damage. It is possible that methanogenic archaeans (including Methanobrevibacter oralis and other Methanobrevibacter species) also contribute to disease progression as some species have been identified in patients with periodontal disease, but this has proven difficult to study. Gingivitis is diagnosed by visual inspection, including measuring pockets in the gums, and X-rays, and is usually treated using good dental hygiene and professional dental cleaning, with antibiotics reserved for severe cases.

Periodontitis

Over time, chronic gingivitis can develop into the more serious condition of periodontitis. When this happens, the gums recede and expose parts of the tooth below the crown. This newly exposed area is relatively unprotected, so bacteria can grow on it and spread underneath the enamel of the crown and cause cavities. Bacteria in the gingival space can also erode the cementum, which helps to hold the teeth in place. If not treated, erosion of cementum can lead to the movement or loss of teeth. The bones of the jaw can even erode if the infection spreads. This condition can be associated with bleeding and halitosis (bad breath). Cleaning and appropriate dental hygiene may be sufficient to treat periodontitis. However, in cases of severe periodontitis, an antibiotic may be given. Antibiotics may be given in pill form or applied directly to the gum (local treatment). Antibiotics given can include tetracycline, doxycycline, macrolides or β-lactams. Because periodontitis can be caused by a mix of microbes, a combination of antibiotics may be given.

Trench Mouth

When certain bacteria, such as Prevotella intermedia, Fusobacterium species, and Treponema vicentii, are involved and periodontal disease progresses, acute necrotizing ulcerative gingivitis or trench mouth, also called Vincent's disease, can develop. This is severe periodontitis characterized by erosion of the gums, ulcers, substantial pain with chewing, and halitosis that can be diagnosed by visual examination and X-rays. In countries with good medical and dental care, it is most common in individuals with weakened immune systems, such as patients with AIDS. In addition to cleaning and pain medication, patients may be prescribed antibiotics such as amoxicillin, amoxicillin clavulanate, clindamycin, or doxycycline.

If you have it, you’re not alone. Many adults nationwide have some form of gum disease. It can simply cause swollen gums or give you bad breath. It can also ruin your smile or even make you lose your teeth. The good news is that gum disease can be prevented with daily dental care.

The problem begins with bacteria. Our mouths are packed with these tiny microbes. They combine with mucus and other particles to form a sticky, colorless film—called plaque—on our teeth. Brushing and flossing can get rid of some plaque. But any that remains can harden and form tartar, a yellowish deposit that can become rock-hard.

Plaque and tartar buildup can lead to gum disease—technically known as periodontal disease. The most common and mild type of gum disease is called gingivitis. The gums become red and swollen, and they can bleed easily. Daily brushing and flossing and regular cleanings by dental professionals can usually clear up gingivitis.

If gingivitis is not treated, it can become a more severe type of gum disease called periodontitis. Symptoms of periodontitis include bad breath that won’t go away; gums that are red, swollen, tender or bleeding; painful chewing; and loose or sensitive teeth.

In periodontitis, the gums pull away from the teeth and form “pockets” that become infected. Bacterial toxins and your body’s natural response to infection start to break down the bone and soft tissues that hold teeth in place. If not treated, the tissues will be destroyed. Your teeth may eventually become loose and have to be removed. If you have periodontitis, your dentist may recommend a deep-cleaning method called scaling and root planing. In more severe cases, you may need surgery.

Most people don’t show signs of gum disease until they’re in their 30s or 40s. But getting older doesn’t necessarily mean you’ll get gum disease. Daily dental care and regular visits to your dentist can reduce your risk of gum disease.

Smoking greatly increases your risk for periodontitis—another reason not to smoke. Other factors that boost your risk include hormonal changes in women, certain medications and some illnesses like diabetes, cancer and AIDS.

NIH-supported researchers are working to learn more about preventing and treating gum problems. Some are exploring whether stem cells might help to restore damaged tissues that support the teeth. Others are searching for genes and proteins produced by our bodies and by the bacteria in our mouths to see how they interact to affect gum health.

Some studies suggest that gum disease may increase the risk of heart attack or stroke or cause other health problems. But so far, it hasn’t been confirmed that gum disease contributes to these conditions.

Although many aspects of gum disease are still being investigated, one thing is clear: controlling gum disease can save your teeth. That alone is an excellent reason to take good care of your teeth and gums every day.

To Prevent Gum Disease

• Brush your teeth twice a day with a fluoride toothpaste.
• Floss every day.
• Visit the dentist routinely for a check-up and professional cleaning.
• Don’t smoke.

Did anyone ever tell you that you smell bad? Funky breath or stinky underarms can happen to anyone, at any age. Whether or not you’ve noticed them, some body odors can signal a health problem. But most breath and body odors are normal.

“Bad breath is most often caused by bacteria on the teeth and tongue,” explains Dr. Madeleine S. Deming, an internal medicine expert at the NIH Clinical Center.

It’s normal if your breath smells a little in the morning, especially if you slept with your mouth open. A dry mouth allows bacteria to thrive. Bacteria that live in the mouth can make compounds that have sulfur. These compounds are especially stinky. They can smell like rotten eggs or onion, for example.

If bad breath isn’t cleared up by brushing your teeth or using mouthwash, it may be a sign of another issue. Over time, bacteria can cause tooth decay and gum disease. Decay and gum disease do not smell good. Both require a trip to the dentist for treatment.

Other causes of foul breath odor may be sinus, throat, or lung infections. These need to be treated by a health care professional, too.

Your breath can also carry clues of disease from other parts of your body. That’s because you exhale more than just air. Your breath also contains gassy compounds that move from your organs through the bloodstream into your lungs.

Breath that smells fruity or like rotten apples, for example, can be a sign of diabetes that’s not under control.

Rarely, people can have bad breath because of organ failure. A person with kidney failure may have breath that smells like ammonia or urine. Serious liver disease can make breath smell musty or like garlic and rotten eggs.

Compounds that are transported through the blood can also be released through your sweat glands. That can make your armpits and skin smell bad. It’s normal for stress to cause smelly compounds to be released through your sweat.

But your armpits can smell for other reasons too. Both moisture and hair enable bacteria to thrive. These bacteria can make smelly compounds. Bathing, shaving, and deodorant can help keep these odors in check.

Because certain diseases cause breath or body odors, NIH-supported researchers are developing an electronic “nose” to help doctors detect them. This research is at an early stage. In the lab, scientists can already analyze odor compounds from the body. They’ve even trained dogs to detect signs of certain cancers in breath samples.

If you’re concerned about a new or worsening body odor, “a trip to the doctor for evaluation is always the first step,” Deming advises. “Bad breath is best assessed by a dentist.”

Your dentist can examine your mouth for signs of trouble. If body odor is your concern, your doctor can conduct a physical exam. If needed, your doctor can suggest further tests.

“A trial of avoiding foods that are known to cause body odor may be considered. In rare cases of body odor due to an underlying medical condition, the treatment of that condition may help to manage the odor as well,” Deming says.

Concerned About a Body Odor?

To prevent strong breath or body odor:

• Bathe, wear clean clothes, and use deodorant.
• Clean and care for your teeth and mouth.
• Keep your mouth moist and your body dry.
• Avoid eating onions, garlic, and other strong-smelling foods.

When you open your mouth to talk, you probably want your friends to think about what you’re saying — and not about what you ate for lunch. But certain strong-smelling foods like onions and garlic can cause bad breath. So can smoking. And so can bacteria that grow on bits of food that get stuck between your teeth.

Lots of people have bad breath at some point. Don’t worry! There are steps you can take to keep your mouth fresh and healthy.

Tips for preventing bad breath

• Brush your teeth (and tongue!) for at least two minutes twice a day with fluoride toothpaste, especially after meals and at bedtime.
• Ask your dentist how to floss correctly. Flossing can remove tiny bits of food that can rot and smell bad.
• Replace your toothbrush every three to four months.
• Visit your dentist twice a year. He or she will help keep your teeth and your mouth healthy.
• Eat smart. Avoid foods and drinks that can leave behind strong smells, like cabbage, garlic, raw onions, and coffee. If you’re trying to lose weight, remember that not eating enough or cutting out certain foods (such as carbohydrates) can cause bad breath.
• Don’t smoke! You’ll smell sweeter — and be lots healthier.
• Drink enough fluids. Drinking helps wash away tiny bits of food and bacteria, which can smell bad.

If your bad breath doesn’t go away, be sure to talk to your dentist, doctor, or nurse. It could be a sign of a medical problem, such as a sinus infection or gum disease. You may feel a little funny talking about bad breath, but it’s very common and you can get help.

Tips for keeping your mouth healthy

A lot of the tips for keeping your mouth healthy are the same as the tips for stopping bad breath, such as brushing and flossing. Below are some more tips for good oral hygiene, which is just a fancy way to say taking care of your teeth and mouth. Do you feel like they are a pain? Well, they are a lot less of a pain than the dentist’s drill!

• Eat smart. Avoid sugary foods and drinks. This helps prevent damage to your teeth and is great for your overall health.
• Brush after sweets. If you eat or drink sugary stuff, try to brush right after. If you can’t brush, at least rinse your mouth with water.
• Definitely don’t smoke. Smoking doesn’t just smell bad and stain your teeth. It also can increase your risk of gum disease and tooth decay.