How can I tell if I have bad breath?

You largely cannot - the nose adapts to constant smells, which is why people are so often unaware. The reliable method is asking someone you trust to be honest. Licking the inside of your wrist, letting it dry and then smelling it gives a rough indication of what others notice.

Why do I still have bad breath after brushing?

Usually because brushing alone is not reaching the cause. The most common culprits are the back of the tongue and the spaces between teeth, neither of which a toothbrush cleans properly. If tongue cleaning and flossing for two weeks make no difference, the cause is likely gum disease, decay, or something outside the mouth.

Does mouthwash cure bad breath?

It can help as part of a routine, but it does not cure anything on its own. If the smell returns within an hour of rinsing, the mouthwash is masking rather than treating, and the underlying cause still needs identifying.

Can bad breath be a sign of something serious?

Occasionally. Persistent bad breath with no dental cause can relate to sinus or tonsil infections, reflux, or less commonly to diabetes, kidney or liver conditions. This is uncommon, but it is the reason a dentist who finds nothing wrong will often refer you on. You can discuss it during a telehealth GP consultation if that is easier than attending a clinic.

Can medications cause bad breath?

Yes, and it is more common than most people realise - usually indirectly, by reducing saliva. Blood pressure medicines, antihistamines, antidepressants and bladder medicines are frequent contributors. Never stop a prescribed medication on your own; raise it with your doctor, who can consider whether an alternative is suitable.

Bad Breath: Causes, Treatment and How to Get Rid of It

Almost everyone wakes up with it. For most people it disappears after brushing and a glass of water, and that is the end of it. Bad breath becomes worth looking into when it sticks around through the day, when it comes back no matter how carefully you brush, or when someone close to you finally says something. At that point it is usually telling you about something happening in the mouth, and occasionally about something happening elsewhere in the body. If an underlying infection seems likely, a telehealth GP consultation or after-hours urgent care can help you work out what is going on.

This guide covers what causes bad breath, what actually helps, how to choose a mouthwash or toothpaste sensibly, and the point at which it stops being a hygiene question and becomes a medical one.

What causes bad breath?

Bad breath, medically called halitosis, is caused overwhelmingly by bacteria living in the mouth. These bacteria break down food particles and proteins, and the compounds they release are what produce the smell. Everything else on the list below is really a variation on the same theme: something that lets those bacteria multiply, or something that reduces the saliva that normally keeps them in check.

Oral causes (around 85 to 90 per cent of cases)

Plaque build-up and gum disease, including gingivitis and periodontitis
Tooth decay, and old or failing fillings and crowns that trap food
Bacteria coating the back of the tongue, which is one of the most commonly missed causes
Food trapped between teeth, under bridges or around wisdom teeth
Dentures or plates that are not cleaned thoroughly or are left in overnight
Mouth infections, ulcers or healing extraction sites

Dry mouth

Saliva is the mouth's own cleaning system. When it drops off, bacteria flourish. This is why morning breath exists at all, and why bad breath is common in people who breathe through their mouth, snore, are dehydrated, or take medicines that dry the mouth as a side effect. A surprising number of common medications do this, including some for blood pressure, allergies, depression and bladder problems.

Food, drink and smoking

Garlic, onion, spices, coffee and alcohol all produce odour compounds that are absorbed into the bloodstream and then breathed out through the lungs. That is why brushing does not fix garlic breath - the smell is not coming from your mouth, it is coming from your lungs, and it has to wear off. Smoking and vaping both dry the mouth and add their own smell on top.

Nose, sinus and throat causes

Sinus infections, post-nasal drip, chronic allergies and tonsillitis can all cause persistent bad breath. So can tonsil stones - small accumulations of debris in the tonsil crevices that have a particularly strong smell and often go unnoticed by the person who has them.

Digestive and medical causes

Reflux (GORD) can push stomach contents far enough up to affect the breath. Less commonly, bad breath relates to a broader medical condition - poorly controlled diabetes, kidney or liver problems, or certain infections can each produce a characteristic breath odour. These are a small minority of cases, but they are the reason persistent bad breath with no dental explanation deserves a medical review rather than more mouthwash.

Crash diets and fasting

Very low-carbohydrate diets and extended fasting push the body into ketosis, which produces a distinctly sweet or fruity breath odour. It is not a sign of anything wrong, and it resolves when eating returns to normal.

How to get rid of bad breath: what actually works

Most bad breath responds to doing the basics properly rather than to buying something new. In rough order of how much difference they tend to make:

1. Clean your tongue

This is the step most people skip, and for a lot of people it is the single biggest improvement. The back of the tongue holds a substantial bacterial load. A tongue scraper or the back of a toothbrush, used gently from back to front, makes a noticeable difference within days.

2. Clean between your teeth, every day

Brushing reaches roughly 60 per cent of the tooth surface. The rest is between the teeth, which is exactly where food gets trapped and gum disease begins. Floss or interdental brushes are not an optional extra here - for persistent bad breath they are often the fix.

3. Brush twice daily with a fluoride toothpaste

Two minutes, twice a day, including along the gum line. Replace the brush every three months or when the bristles splay.

4. Keep your mouth moist

Drink water regularly through the day. Sugar-free gum stimulates saliva and is genuinely useful after meals when brushing is not practical. If your mouth is persistently dry, mention it to your pharmacist or doctor - saliva substitutes exist, and it is worth checking whether a medication you take is the cause.

5. See a dentist

If bad breath persists despite all of the above, a dentist is the right next step rather than a doctor. Gum disease and decay are the most common causes, and neither improves without treatment. A professional clean removes hardened plaque that brushing cannot touch.

Mouthwash for bad breath: what to look for

Mouthwash is useful as an addition to brushing and flossing, and close to useless as a replacement for them. If it is masking a smell that returns within an hour, the underlying cause has not been addressed.

When choosing one, the things worth paying attention to are:

Antibacterial action rather than fragrance alone - a product that only perfumes the breath buys you about twenty minutes
Alcohol-free formulations, which are generally preferable if you have a dry mouth, since alcohol dries it further
Fluoride content, if decay risk is also a concern
How long it is meant to be used - some antibacterial rinses, particularly chlorhexidine-based ones, are intended for short courses under professional supervision rather than indefinite daily use

There is no single best mouthwash for bad breath, because the right choice depends on what is causing yours. Someone with gum disease, someone with a medication-related dry mouth, and someone with tonsil stones all need different things. Your pharmacist or dentist can point you to a suitable option for your situation.

Toothpaste for bad breath

Toothpaste matters less than technique. Any fluoride toothpaste used properly for two minutes twice a day will do more than an expensive one used for thirty seconds.

That said, if you are selecting with bad breath in mind: look for fluoride as the baseline, consider a formulation aimed at gum health if your gums bleed when you brush, and look for one designed for dry mouth if that is your issue. Whitening toothpastes do nothing for breath. If a particular toothpaste stings or dries your mouth, that is a reason to switch rather than persist.

About oral care products: this article does not recommend or endorse any specific brand or product. Some mouthwashes and toothpastes are regulated therapeutic goods. Always read the label, use only as directed, and ask your pharmacist, dentist or doctor what is appropriate for your circumstances.

When bad breath needs medical attention

Book in with a doctor rather than only a dentist if bad breath comes with any of the following:

Persistent bad breath that your dentist has investigated and found no dental cause for
A sore throat, swollen tonsils, white patches on the tonsils, or difficulty swallowing
Ongoing nasal congestion, facial pain or post-nasal drip
Heartburn, regurgitation or a persistent sour taste
Unexplained weight loss, excessive thirst or frequent urination
A persistently dry mouth, especially if you take regular medications
A sudden change in the smell or taste in your mouth with no obvious explanation

Difficulty breathing or swallowing, drooling, severe throat swelling or a muffled voice can indicate a serious airway problem. Call 000 or attend your nearest emergency department immediately.

Dentist or doctor: which one?

As a rough rule, start with a dentist. The large majority of bad breath is dental in origin, and a dentist can examine the teeth and gums directly, which a doctor is not set up to do.

A doctor is the right starting point when the bad breath arrives alongside symptoms that are clearly not dental - a sore throat and fever, sinus pain, reflux, or a dry mouth that started after a new medication. 13CURE takes bookings Monday to Friday from 6pm through to 8am, Saturdays from 12pm, and 24 hours on Sundays and public holidays, for non-life-threatening concerns. Consultations are bulk billed for eligible Medicare and DVA cardholders, and the bulk billing GP page sets out how eligibility is assessed.

A bulk billed telehealth appointment suits most of these conversations, since a GP can take a history, review your medications and advise on next steps. Where an in-person examination is needed, a home doctor visit may be available depending on your location - the areas we cover page lists current coverage.