Why do I have bad breath that won't go away even after brushing?

Because brushing cannot reach the source. The most common cause of bad breath that won't go away is periodontal (gum) disease: deep gum pockets form beside the tooth root, and the anaerobic bacteria inside them break down proteins into volatile sulphur compounds all day long. A toothbrush reaches roughly 1-2 mm below the gum line; a 6 mm pocket is untouched. Other causes include a decaying tooth or failing filling, tonsil stones, chronic dry mouth, and sinus or post-nasal drip. Persistent bad breath is a symptom, not a hygiene failure.

When should I see a dentist about bad breath?

Book a dentist if your bad breath persists for more than two to three weeks despite twice-daily brushing, daily interdental cleaning and daily tongue cleaning. Book sooner if you also have bleeding gums, receding gums, a persistent bad taste, loose teeth, or a spot in your mouth where food constantly packs. Ask specifically for a periodontal examination with pocket charting.

Can gum disease cause bad breath?

Yes - it is the most common cause of persistent bad breath. Deep periodontal pockets are low-oxygen, protein-rich spaces colonised by anaerobic bacteria that produce volatile sulphur compounds. Methyl mercaptan, the rotting-cabbage gas, is particularly associated with periodontal disease (Yaegaki & Sanada, Journal of Periodontal Research, 1992). Bleeding gums, receding gums and a persistent bad taste alongside bad breath point strongly toward gum disease.

Does bad breath come from the stomach?

Usually not. The oesophagus is a closed muscular tube, not an open pipe venting gas into the mouth. The overwhelming majority of persistent bad breath originates in the mouth and throat - gum pockets, tongue coating, decayed teeth, tonsils. The honest exception is significant reflux (GORD), which can contribute and is worth raising with a GP. But the belief that bad breath is a stomach problem keeps people looking in the wrong place for years.

What are tonsil stones and can they cause bad breath?

Tonsil stones (tonsilloliths) are small calcified lumps of debris, dead cells, mucus and bacteria that form in the crypts of the tonsils. They smell extremely foul and are a genuine cause of severe bad breath. Signs include a feeling of something stuck in the throat, small white or yellow lumps visible at the back of the throat, and occasionally coughing one up. They are usually harmless. A GP can advise and can refer to an ENT specialist if they recur. Do not dig at your tonsils with sharp objects.

Can medication cause bad breath?

Yes - indirectly, by causing dry mouth. Hundreds of common medications list xerostomia (dry mouth) as a side effect, including antidepressants, antihistamines, blood pressure medicines and diuretics. Without saliva, the mouth loses its natural cleansing and buffering, and odour-producing bacteria flourish. Never stop or change a prescribed medication yourself - ask your pharmacist for a medicines review, or raise it with your GP.

What if my dentist says my breath is fine but I'm sure it isn't?

This is recognised clinically and it is not a dismissal. Yaegaki and Coil (Journal of the Canadian Dental Association, 2000) distinguished genuine halitosis, pseudo-halitosis and halitophobia. A dentist can objectively measure breath, including instruments that detect volatile sulphur compounds. If the measurement is clean, the distress is still completely real - and health anxiety of this kind responds well to treatment. Talk to your GP. Either way, you get an answer.

Will mouthwash fix bad breath that won't go away?

No. Mouthwash flows over the opening of a periodontal pocket - it does not penetrate to the bottom of one, and it cannot reach inside a decayed tooth or a tonsillar crypt. A Cochrane review of interventions for halitosis (Kumbargere Nagraj et al., 2019) found the evidence for such products to be low-certainty and short-lived: they mask or briefly reduce odour rather than resolve its source. Freshness products have a place in a daily routine. They are not a diagnosis.

Bad Breath That Won't Go Away: When To See A Dentist

📖 13 min read · Updated 15/08/2026

Quick Summary

❌ Bad breath that survives good brushing, daily flossing and daily tongue cleaning is NOT a hygiene failure — it is a symptom

✔ The single most common cause is periodontal (gum) disease — the bacteria in deep gum pockets are exactly the ones that produce the worst-smelling sulphur gases

✔ You cannot brush a periodontal pocket clean. No toothpaste, mouthwash or scraper reaches the bottom of one. It needs professional treatment

✔ Other real causes: a decaying tooth or leaking filling, tonsil stones, chronic dry mouth, sinus and post-nasal drip, and — rarely — systemic disease

❌ Persistent bad breath does NOT usually come from your stomach. That belief keeps people looking in the wrong place for years

✔ One dental appointment, with your gum pockets charted, finds the cause in the large majority of cases

✔ Say this at the desk: “I have persistent bad breath. I want my gums checked and my teeth checked for decay.”

Quick Answer

Bad breath that won’t go away — breath that persists despite twice-daily brushing, daily interdental cleaning and daily tongue cleaning — is a symptom, not a hygiene failure. The most common cause by far is periodontal (gum) disease. Deep periodontal pockets are low-oxygen, protein-rich spaces, and the anaerobic bacteria that live in them break down proteins into volatile sulphur compounds (VSCs) — the gases that make breath smell. Methyl mercaptan, the rotting-cabbage VSC, is particularly associated with periodontal disease (Yaegaki & Sanada, Journal of Periodontal Research, 1992). Other common drivers include a decaying tooth or failing filling, tonsil stones, chronic dry mouth, and sinus or post-nasal drip. The action is the same: book a dentist and ask for a periodontal examination. Do NOT keep buying stronger mouthwash.

First, The Threshold: What This Article Is Actually About

Morning breath is normal. Saliva flow drops while you sleep, bacteria multiply undisturbed for eight hours, and you wake up with a mouth that smells. It clears within minutes of brushing. Breath after garlic, onion, coffee or alcohol is also normal — those odours are carried in the bloodstream and exhaled through the lungs, which is why brushing barely touches them and why they fade on their own over the following hours.

Neither of those is what this article is about.

This article is about breath that is still there at 11am. Breath that is still there after you brushed twice, flossed every gap, scraped your tongue, and switched to the strongest mouthwash on the shelf. Breath that your partner has mentioned, or that you have learned to read in the faces of people standing close to you. Breath that has lasted weeks, months, or years.

The threshold for escalation

If your breath is bad despite twice-daily brushing, daily interdental cleaning and daily tongue cleaning — sustained for at least two to three weeks — you have crossed the line where more products will NOT help. You need a diagnosis, not a purchase.

That distinction matters more than anything else here. Persistent bad breath is NOT a character flaw, a cleanliness failure, or something you brought on yourself by being lazy. It is a signal that something in your mouth, throat or nose is producing odour faster than hygiene can remove it. Something is generating it. Your job is to find out what.

Cause 1 — Periodontal (Gum) Disease: The Most Common, And The Most Missed

If you take one thing from this article, take this. The most likely explanation for bad breath that will not go away is periodontal disease — gum disease that has progressed past surface gingivitis and started destroying the attachment between gum and tooth.

Here is the mechanism, and it is worth understanding, because once you understand it you will stop blaming yourself. When gum disease advances, the gum detaches from the tooth surface and a pocket forms — a narrow space running down the side of the root, below the gum line. A healthy sulcus is around 1–3 mm deep. A diseased pocket can be 5, 7, 9 mm or more.

That pocket is a near-perfect habitat for the worst possible bacteria. It is dark. It is warm. It is starved of oxygen. And it is bathed in a constant supply of protein — from crevicular fluid, from blood if the gums are inflamed, from dying tissue cells. The bacteria that thrive there are anaerobic protein-degraders: they cannot survive in oxygen, and they feed by breaking proteins down into their component amino acids.

Why That Produces The Specific Smell

When those bacteria break down sulphur-containing amino acids — cysteine and methionine — the waste products are volatile sulphur compounds (VSCs). Three matter most:

Gas	What it smells like	Where it comes from
Hydrogen sulphide (H₂S)	Rotten eggs	Broadly produced across the mouth — heavily on the back of the tongue
Methyl mercaptan (CH₃SH)	Rotting cabbage, faecal	Strongly associated with periodontal disease — the pocket gas
Dimethyl sulphide	Sweetish, sulphurous	More often linked to sources outside the mouth (blood-borne, systemic)

That middle row is the important one. Research going back decades has found that the ratio of methyl mercaptan to hydrogen sulphide in mouth air is markedly higher in people with periodontal disease than in people with healthy gums — a finding published by Yaegaki and Sanada in the Journal of Periodontal Research (1992) and repeatedly supported since. Foundational work by Tonzetich (Journal of Periodontology, 1977) established VSCs as the primary chemical basis of oral malodour in the first place.

In plain terms: if your bad breath has a heavy, rotting, almost faecal edge to it rather than a simple stale smell — and if it will not shift no matter what you do — gum disease is the first thing that should be ruled out. Not the last.

The Tells — What Else You Would Notice

Sign	What you would actually notice
Bleeding gums	Pink in the sink after brushing or flossing. Even ‘a little bit sometimes’ counts.
Red, puffy, shiny gums	Healthy gums are firm and pale pink. Inflamed gums look swollen and darker.
Receding gums	Teeth look longer. Gaps opening at the gum line. Cold sensitivity on the roots.
A bad taste, not just a bad smell	A persistent metallic or foul taste is one of the most telling signs of a pocket.
Teeth that feel loose or have shifted	Late sign. Gaps appearing where there were none. A bite that feels different.
Gum tenderness or a dull ache	Often mild. Periodontitis is famously painless until it is advanced — do NOT wait for pain.

Read that list carefully. Many people with persistent bad breath tick three or four of those boxes and have never connected them to their breath. They are the same disease. See 7 Warning Signs Of Gum Disease You Should Never Ignore for the full picture.

Periodontitis is not rare in this country. The National Study of Adult Oral Health 2017–18 (Australian Research Centre for Population Oral Health, University of Adelaide) found moderate or severe periodontitis in roughly three in ten Australian adults. Most of them do not know they have it, because in its early and middle stages it does not hurt.

Why You Cannot Brush A Periodontal Pocket Clean

This is the section that explains the last two years of your life, and it is why the whole ‘try a stronger product’ approach has failed you.

The hard truth

A toothbrush bristle reaches about 1–2 mm below the gum line. Floss reaches a little further. Mouthwash does not penetrate a deep pocket — it flows over the opening. If your pocket is 6 mm deep, the bottom 4 mm has never been touched by anything you have ever bought. This is NOT your fault. It is anatomically impossible.

The bacteria at the bottom of that pocket are undisturbed, permanently fed, and permanently producing gas. The gas escapes into your mouth continuously, all day. You brush, and for twenty minutes your breath is fine. Then the pocket refills the air in your mouth and you are back where you started. That cycle — brief improvement, rapid return — is one of the most recognisable patterns in persistent halitosis, and it is almost diagnostic of a source you cannot physically reach.

What actually clears it is professional periodontal treatment: a dentist or periodontist charting the depth of every pocket around every tooth, then debriding them — scaling and root planing under the gum, often over more than one appointment, sometimes with local anaesthetic. That physically removes the biofilm and calculus from the root surface inside the pocket. Home care then keeps it from coming back. Home care alone was never going to fix it.

A Cochrane systematic review of interventions for halitosis (Kumbargere Nagraj and colleagues, Cochrane Database of Systematic Reviews, 2019) looked at the products people reach for and concluded that the evidence for most of them is low-certainty and short-lived — they mask or briefly reduce odour rather than resolve its source. That is not an argument against fresh breath products. It is an argument for finding the source first.

Cause 2 — A Decaying Tooth, A Failing Filling Or A Leaking Crown

The second most common dental cause is a physical defect somewhere in your mouth that is trapping food and bacteria in a place you cannot clean.

A cavity is a hole. Food packs into it, sits there, and rots. A filling that has cracked or pulled away from the tooth leaves a microscopic gap that leaks — and decay quietly spreads underneath it, out of sight and out of reach. A crown with a failing margin does the same. An old root canal that has become reinfected can produce a genuinely foul smell, sometimes with a small gum boil or a pimple-like spot on the gum above the tooth.

The useful clue with this cause is localisation. People can often tell, if they pay attention, that the bad taste or smell is coming from one particular side or one particular area. Food gets stuck in the same spot every meal. Floss comes out of one specific gap smelling far worse than the others. That is a strong signal — and it is exactly the kind of thing an X-ray and an examination will settle in one visit.

Fixed by: a dentist. This is a repair job, and it is usually straightforward once identified.

While You Sort Out The Cause, Keep The Daily Routine Honest

LACALUT^® Flora is a two-part daily freshness routine formulated to target the bacteria behind bad breath. It is a cosmetic routine — not a substitute for a dental examination. If your breath persists, see a dentist.

View LACALUT Flora

Cause 3 — Tonsil Stones (Tonsilloliths)

Tonsil stones are small, calcified lumps of debris that form in the crypts — the folds and pits — of the tonsils. Dead cells, mucus, food particles and bacteria collect in the crevice, compact, and harden. They are usually white or pale yellow, often the size of a grain of rice, sometimes larger.

They smell appalling. Genuinely, disproportionately appalling for something so small.

The cruel part is that most people who have them do not know. The stones sit at the back of the throat, out of the line of sight, and the person carrying them cannot smell their own breath — the olfactory system adapts to a constant odour within minutes and simply stops reporting it.

Signs You Might Have Them

Sign	Detail
A feeling of something stuck	A persistent sensation of a lump, tickle or irritation in the throat that never quite clears
Visible white or yellow lumps	Look at the back of your throat in a mirror with a torch. Small pale specks in the tonsil folds
Coughing up small hard lumps	Occasionally one dislodges. People describe them as foul-smelling and chalky
Breath that is bad despite clean, healthy gums	If a dentist has checked your gums and teeth and found nothing, look upwards and backwards
A sore throat or ear-referred ache on one side	Larger stones can irritate the tonsil tissue

Tonsil stones are usually harmless. They are not an infection in the dangerous sense and they very rarely indicate anything sinister. But they are a real, physical, entirely legitimate cause of severe bad breath, and they are commonly missed — because a dentist checks teeth and gums, and a GP does not routinely look for them unless prompted.

If you find them: a GP can advise, and can refer to an ENT (ear, nose and throat) specialist if they recur persistently or are large. Options range from gentle at-home dislodgement and saltwater gargling through to, in severe recurrent cases, surgical management. Be honest with yourself — if you have recurrent tonsil stones, that is a conversation with a doctor, not a shopping decision. Do NOT dig at your tonsils with sharp objects. You will damage the tissue and make the crypts worse.

Cause 4 — Chronic Dry Mouth (Xerostomia)

Saliva is not incidental. It is the mouth’s cleaning and buffering system: it washes away food debris and dead cells, dilutes bacterial waste, delivers oxygen to the tissues (which anaerobic bacteria hate), and neutralises acid. Take saliva away and the odour-producing bacteria get a free run.

This is why breath is worst first thing in the morning — salivary flow drops to near-nothing overnight. Now imagine that state persisting all day, every day. That is chronic dry mouth, and it is one of the most under-recognised causes of persistent halitosis in adults.

What Causes It

Driver	Detail
Medication — by far the biggest cause	Hundreds of common drugs list dry mouth as a side effect: antidepressants, antihistamines, blood pressure medicines, diuretics, some painkillers, ADHD medication, and many more. Taking several at once compounds it
Mouth breathing	Bypasses the nose, dries the oral tissues directly. Often worse at night
Sleep apnoea and snoring	Hours of open-mouth breathing every night. A very common hidden driver
Dehydration	Simple, common, and easily fixed — but rarely the whole story on its own
Sjögren’s syndrome	An autoimmune condition that attacks the salivary and tear glands. Needs a GP
Radiotherapy to the head or neck	Can permanently reduce salivary gland function. Managed with a dentist and specialist
Age and reduced fluid intake	Salivary flow tends to decline — often alongside a longer medication list

Read this before you touch your prescriptions

If you suspect a medication is drying your mouth out, do NOT stop taking it and do NOT change your dose. Book a free medicines review with your pharmacist, or raise it with your GP. There is frequently an alternative drug, a different dose, or a change of timing that helps — but that is a clinical decision, not a self-service one.

More on this: How Your Medication Is Causing Bad Breath And Dry Mouth and Dry Mouth At Night: Causes And Fixes.

Cause 5 — Sinus Problems, Post-Nasal Drip And Tonsillitis

Chronic sinusitis, allergic rhinitis and post-nasal drip all do the same thing: they deposit a continuous stream of protein-rich mucus onto the back of the tongue and throat. That mucus is food. The anaerobic bacteria living on the posterior tongue break it down, and the by-products are the same volatile sulphur compounds we started with.

The tells are usually obvious once you look for them: a constant need to clear your throat, a feeling of mucus running down the back of your nose, blocked or congested nasal breathing, a chronic cough that is worse when lying down, or a history of hay fever and sinus infections. Recurrent tonsillitis does the same thing by a different route — inflamed, infected tonsil tissue is itself an odour source.

Fixed by: a GP first, then an ENT specialist if it does not resolve. Treating the underlying nasal or sinus condition often clears the breath as a side effect — because the fuel supply is cut off at the source.

Cause 6 — The Rare Systemic Causes (Read This Calmly)

A small number of medical conditions can change the smell of breath, because the compounds responsible are carried in the blood and released through the lungs rather than produced in the mouth. They are genuinely uncommon as a cause of everyday persistent bad breath, and they almost never present with bad breath as the only symptom.

Condition	Classically described breath	Would normally come with
Uncontrolled diabetes / ketoacidosis	Sweet, fruity, acetone-like — nail-polish-remover	Extreme thirst, frequent urination, weight loss, fatigue. Acute ketoacidosis is a medical emergency
Advanced liver disease	Musty, sweetish	Jaundice, abdominal swelling, fatigue — not an isolated finding
Advanced kidney disease	Ammonia-like, fishy, urine-like	Fatigue, swelling, changes in urination
Certain metabolic conditions	Various distinctive odours	Usually diagnosed in childhood

How to hold this information

Do NOT read that table and diagnose yourself with a serious illness. Bad breath on its own, with no other symptoms, is overwhelmingly likely to be dental. But if your breath has a distinctly sweet, fruity, ammonia-like or otherwise unusual character — and especially if you also feel unwell, unusually thirsty, exhausted, or you are losing weight — that is a conversation to have with your GP. Not a reason to panic. A reason to book.

The Stomach Myth — And Why It Costs People Years

Almost everybody with persistent bad breath eventually decides it is coming from their stomach. It is one of the most durable beliefs in oral health, and it is, in the great majority of cases, wrong.

The oesophagus is a collapsed muscular tube. It is closed. It is not an open pipe venting stomach gas into your mouth — it opens when you swallow, belch or vomit, and otherwise it stays shut. If bad breath were routinely coming up from the stomach, you would notice it as a discrete event, not as a constant background smell.

The halitosis literature is consistent on this: the overwhelming majority of persistent bad breath originates inside the mouth and throat — the tongue coating, the periodontal pockets, the tonsils, the decayed teeth. Not the gut. Every month spent on stomach remedies, digestive supplements and elimination diets is a month the actual cause spends untreated.

The honest exception: significant gastro-oesophageal reflux (GORD) is real, and can genuinely contribute — both by bringing acid and material up, and by eroding the teeth. If you have frequent heartburn, regurgitation or a chronic acid taste, raise it with your GP. But reflux should be added to the list of possibilities, not used to replace the dental examination you have been avoiding.

For the microbiology of where the smell really comes from, see Why Do Some People Always Have Bad Breath? The Bacterial Truth and Does Tongue Scraping Work?.

When You Are Certain And Everyone Tells You It Is Fine

There is a group of people this article must not leave behind: those who are utterly convinced they have terrible breath, who have reorganised their social life around it, and who — when the breath is objectively measured — do not have it.

This is recognised clinically. Yaegaki and Coil described the classification in the Journal of the Canadian Dental Association (2000): genuine halitosis (measurable odour), pseudo-halitosis (no measurable odour, but the person believes there is, and is reassured by being told so), and halitophobia (the belief persists even after treatment and after objective measurement shows nothing).

That is not being told you are imagining things. It is not a dismissal, and it is certainly nothing to be embarrassed about. The distress is completely real, whatever the measurement says — and it is treatable. A dentist can objectively measure your breath, including with instruments that detect volatile sulphur compounds directly. If that measurement comes back clean, the appropriate next step is a kind conversation with your GP about the anxiety itself, which responds well to treatment. Either way you get an answer. Both answers are worth having.

Every Cause At A Glance — And Exactly Who Fixes It

Cause	Tell-tale sign	Who fixes it
Periodontal (gum) disease — most common	Bleeding or receding gums, a bad taste as well as a smell, loose or shifted teeth. Breath returns within an hour of brushing	Dentist or periodontist — pocket charting, then scaling and root planing
Decayed tooth, failing filling, leaking crown, reinfected root canal	Localised — you can often tell which side. Food packs in the same spot. Floss from one gap smells far worse	Dentist — X-ray, then repair
Heavy tongue coating	Visible white or yellow film across the back of the tongue	You — daily tongue cleaning. If the smell persists despite it, the source is elsewhere
Tonsil stones	Something stuck in the throat; small white or yellow lumps at the back; occasionally coughed up	GP, then ENT if recurrent. Usually harmless
Chronic dry mouth	Mouth feels dry all day, difficulty swallowing dry food, sticky saliva. Often on multiple medications	Pharmacist (medicines review) or GP. NEVER stop a prescribed medication yourself
Sinusitis / post-nasal drip / rhinitis	Constant throat clearing, blocked nose, mucus down the back of the throat, worse lying down	GP, then ENT
Recurrent tonsillitis	Repeated sore throats, swollen tonsils, fever episodes	GP, then ENT
Reflux (GORD)	Frequent heartburn, regurgitation, chronic acid taste, dental erosion	GP
Systemic causes (rare)	Distinctly sweet/fruity, ammonia-like or unusual breath plus feeling unwell, thirsty, exhausted, losing weight	GP — promptly, but without panic
Pseudo-halitosis / halitophobia	Nobody else can detect it; objective measurement is clean; the fear persists regardless	Dentist (to measure) then GP (to treat the anxiety) — both legitimate

The Appointment: What To Book, And What To Say

Here is the single most useful action available to you. It takes one phone call and roughly one hour of your life, and it identifies the cause in the large majority of cases.

Say exactly this

“I have persistent bad breath. I want my gums checked and my teeth checked for decay.” Ask specifically for a periodontal examination with pocket charting.

That last phrase matters. Pocket charting is the procedure where the dentist or hygienist runs a small graduated probe around every tooth and records the depth of the gum pocket at six points on each one. It is quick, it is not painful, and it produces a numerical map of your gums. Numbers of 1–3 with no bleeding are healthy. Fours and above, especially with bleeding on probing, mean disease — and mean a source of odour that no product you own has ever reached.

What happens at the appointment	What it rules in or out
Periodontal pocket charting	Gum disease — the most common cause of persistent bad breath
Visual examination and X-rays	Decay, failing fillings, leaking crowns, reinfected root canals, abscesses
Tongue and soft tissue examination	Heavy tongue coating; other oral sources
Questions about your medications and medical history	Dry mouth; systemic contributors; reflux
Objective odour assessment (some clinics)	Genuine halitosis versus pseudo-halitosis

One more thing, and it is the reason people delay for years. Dentists are not shocked by bad breath. They see it constantly, they know exactly what causes it, and they know it is a medical finding rather than a moral one. You are NOT going to embarrass yourself. You are going to walk out with an answer you have been chasing on your own, unsuccessfully, for a very long time.

Fresh Breath Is A Daily Routine — A Diagnosis Is A Dental Appointment

LACALUT^® Flora is a two-part cosmetic freshness routine, formulated to target the bacteria behind bad breath. It supports good daily hygiene. It does NOT replace a periodontal examination — if your breath persists, book the dentist first.

View LACALUT Flora

Also worth reading: The Best Toothpaste For Bad Breath In Australia — and if your gums are bleeding, start with 7 Warning Signs Of Gum Disease.

Medical disclaimer: This article is for general information only and does not constitute dental or medical advice. Persistent bad breath should be assessed by a registered dental practitioner. Never start, stop or change a prescribed medication without speaking to your doctor or pharmacist.

Frequently Asked Questions — Persistent Bad Breath

Question	Answer
Why do I have bad breath that won't go away even after brushing?	Because brushing cannot reach the source. The most common cause of bad breath that won't go away is periodontal (gum) disease: deep gum pockets form beside the tooth root, and the anaerobic bacteria inside them break down proteins into volatile sulphur compounds all day long. A toothbrush reaches roughly 1-2 mm below the gum line; a 6 mm pocket is untouched. Other causes include a decaying tooth or failing filling, tonsil stones, chronic dry mouth, and sinus or post-nasal drip. Persistent bad breath is a symptom, not a hygiene failure.
When should I see a dentist about bad breath?	Book a dentist if your bad breath persists for more than two to three weeks despite twice-daily brushing, daily interdental cleaning and daily tongue cleaning. Book sooner if you also have bleeding gums, receding gums, a persistent bad taste, loose teeth, or a spot in your mouth where food constantly packs. Ask specifically for a periodontal examination with pocket charting.
Can gum disease cause bad breath?	Yes - it is the most common cause of persistent bad breath. Deep periodontal pockets are low-oxygen, protein-rich spaces colonised by anaerobic bacteria that produce volatile sulphur compounds. Methyl mercaptan, the rotting-cabbage gas, is particularly associated with periodontal disease (Yaegaki & Sanada, Journal of Periodontal Research, 1992). Bleeding gums, receding gums and a persistent bad taste alongside bad breath point strongly toward gum disease.
Does bad breath come from the stomach?	Usually not. The oesophagus is a closed muscular tube, not an open pipe venting gas into the mouth. The overwhelming majority of persistent bad breath originates in the mouth and throat - gum pockets, tongue coating, decayed teeth, tonsils. The honest exception is significant reflux (GORD), which can contribute and is worth raising with a GP. But the belief that bad breath is a stomach problem keeps people looking in the wrong place for years.
What are tonsil stones and can they cause bad breath?	Tonsil stones (tonsilloliths) are small calcified lumps of debris, dead cells, mucus and bacteria that form in the crypts of the tonsils. They smell extremely foul and are a genuine cause of severe bad breath. Signs include a feeling of something stuck in the throat, small white or yellow lumps visible at the back of the throat, and occasionally coughing one up. They are usually harmless. A GP can advise and can refer to an ENT specialist if they recur. Do not dig at your tonsils with sharp objects.
Can medication cause bad breath?	Yes - indirectly, by causing dry mouth. Hundreds of common medications list xerostomia (dry mouth) as a side effect, including antidepressants, antihistamines, blood pressure medicines and diuretics. Without saliva, the mouth loses its natural cleansing and buffering, and odour-producing bacteria flourish. Never stop or change a prescribed medication yourself - ask your pharmacist for a medicines review, or raise it with your GP.
What if my dentist says my breath is fine but I'm sure it isn't?	This is recognised clinically and it is not a dismissal. Yaegaki and Coil (Journal of the Canadian Dental Association, 2000) distinguished genuine halitosis, pseudo-halitosis and halitophobia. A dentist can objectively measure breath, including instruments that detect volatile sulphur compounds. If the measurement is clean, the distress is still completely real - and health anxiety of this kind responds well to treatment. Talk to your GP. Either way, you get an answer.
Will mouthwash fix bad breath that won't go away?	No. Mouthwash flows over the opening of a periodontal pocket - it does not penetrate to the bottom of one, and it cannot reach inside a decayed tooth or a tonsillar crypt. A Cochrane review of interventions for halitosis (Kumbargere Nagraj et al., 2019) found the evidence for such products to be low-certainty and short-lived: they mask or briefly reduce odour rather than resolve its source. Freshness products have a place in a daily routine. They are not a diagnosis.