Condition Basics

What is bad breath?

Everybody has bad breath from time to time, especially first thing in the morning. Saliva has a cleaning action that helps reduce or get rid of bad breath. When you have less saliva, bacteria can grow, causing bad breath. The flow of saliva almost stops during sleep.

Many other things can cause bad breath, such as missing meals, being dehydrated, or eating foods with a strong odour, such as garlic. Other causes include throat or mouth infections (such as strep throat), dental problems (such as cavities), and gum disease. Bad breath can also be caused by medical problems, such as kidney disease.

What causes it?

Many things can cause bad breath. A major cause is decreased saliva. Saliva has a cleaning action that helps reduce or eliminate bad breath. When saliva decreases, bacteria can grow, causing bad breath.

Bad breath caused by a decrease in saliva may be especially noticeable:

• In the morning. The flow of saliva almost stops during sleep. The reduced cleaning action of the saliva allows bacteria to grow, causing bad breath.
• When you are hungry. Bad breath is more common in people who miss meals or are dieting. Chewing food increases saliva in the mouth. When you are not eating, saliva decreases and bacteria growth increases, causing bad breath.
• When you are dehydrated. When you become dehydrated, you do not produce as much saliva. The reduced cleaning action of the saliva allows bacteria to grow, causing bad breath.
• From diseases that affect the salivary glands, such as Sjögren's syndrome or scleroderma.
• When you are taking certain medicines.
• After drinking alcohol beverages.

Other causes of bad or changed breath include:

• Eating foods with a strong odour, such as garlic, onions, or pastrami.
• Smoking or using smokeless (spit) tobacco, such as snuff or chewing tobacco.
• Bacteria and plaque buildup in the mouth from food caught between teeth, dentures, or dental appliances.

Mouth and throat problems that can cause mouth odour include:

• Throat or mouth infections, such as strep throat.
• Dental problems, such as cavities.
• Gum disease (periodontal disease), which may cause a metallic breath odour.
• Tonsils with deep tunnels (crypts) that trap food particles.
• Throat or mouth cancers.

Problems in other areas of the body that can cause mouth odour include:

• Problems with the nose, such as a sinus infection, nasal polyps, or an object in the nose.
• Diabetes. A symptom of very high blood sugar is a strong, fruity breath odour.
• Digestive system disorders, such as reflux (gastroesophageal reflux disease), bowel problems, or cancer.
• Human immunodeficiency virus (HIV) infection.
• Liver disease.
• Lung problems, such as an infection or cancer.

How can you care for yourself?

Mouth care

• Gargle with water.
• Floss your teeth once each day.
• Use a mouthwash for temporary relief of bad breath. Swish it around in your mouth for 30 seconds before spitting it out.
• Brush your teeth, tongue, roof of the mouth, and gums at least twice a day with toothpaste.
• Remove dentures, removable bridges, partial plates, or orthodontic appliances and clean them once each day or as directed by your dentist. Pieces of food and germs can collect on these appliances and cause bad breath.

Healthy lifestyle

• Eat a low-fat diet rich in fruits and vegetables.
• Eat less meat.
• Don't smoke or use other tobacco products, such as snuff or chewing (spit) tobacco.
• Avoid foods and drinks that cause bad breath, such as garlic and alcohol.
• Eat at regular intervals. Dieting or missing meals can decrease saliva and cause bad breath.
• Chew sugar-free gum, suck on sugar-free mints, or drink water, especially if your mouth is dry. Try using breath sticks, which contain the ingredients found in a mouthwash and dissolve in your mouth.

Doctor visits

• Have regular dental checkups.
• Ask your doctor about making an appointment to see an ear, nose, and throat specialist (otolaryngologist) if you have frequent problems with mouth odour.