Introduction

Lots of people get bad breath at some point. You can get bad breath for a short time if you eat strong-smelling foods, like onions. Or you can get it because of a medical condition, such as gum disease or an infection in your throat. Bad breath can be embarrassing, but there are treatments that can help.

We've brought together the best research about bad breath and weighed up the evidence about how to treat it. You can use our information to talk to your dentist or doctor and decide which treatments are best for you.

Bad breath is an unpleasant smell on your breath. Other people may notice it when you speak or breathe out. You might not be aware of it yourself.

Everyone gets bad breath occasionally, but some medical problems can mean you have it most of the time or even all of the time. Bad breath is sometimes called halitosis.

Temporary bad breath

Lots of people have bad breath first thing in the morning. That's because saliva usually keeps your mouth clean, and it dries up while you sleep.^[1]

'Morning breath' is probably worse in people who tend to breathe through their mouths rather than their noses.^[2] But the problem is easily put right. It will go away as soon as you have something to eat, brush your teeth, or rinse your mouth.

You can also have temporary bad breath after:^[2]

• Eating spicy or strong-smelling foods, like garlic, raw onions, or curry

• Smoking

• Drinking alcohol.

Most people put up with bad breath for a little while if they enjoy these things. But steering clear of alcohol, cigarettes, or spicy food can help you avoid bad breath.

Long-lasting bad breath

Bad breath that lasts through the day is usually caused by a problem in your mouth.^[3] For 9 in 10 people, bad breath is caused by either gum disease or bacteria that grow on your tongue.^[1][3]

However, bad breath is occasionally caused by a medical problem somewhere else in your body. Conditions that can cause bad breath include sinusitis, tonsillitis, and some lung problems or stomach problems.

Bacteria can grow on the coating on the back part of your tongue. As they grow, bacteria give off gases. These gases can make your breath smell bad.

You may be more likely to have this kind of bad breath if you:^[4]

• Smoke

• Don't brush your teeth every day

• Don't produce enough saliva.

Not producing enough saliva can be a problem because saliva helps to keep your mouth clean. You might produce less saliva than usual if you:

• Are taking some medicines, such as antihistamines, antidepressants, or tablets for high blood pressure

• Have problems with the glands in your mouth that make saliva

• Don't drink enough water

• Don't eat regularly enough

• Breathe through your mouth too much.