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Alex Manos | 05 Nov 2025 | Gut Health

How To Get Rid Of Bad Breath

How To Get Rid Of Bad Breath: The Gut-Breath Connection You Need to Know

Bad breath, medically known as halitosis, affects between 15% and 60% of the population worldwide. If you’ve tried every mouthwash, breath mint, and dental hygiene product on the shelf without success, the answer to your persistent bad breath might not be in your mouth at all—it could be in your gut.

What Is Halitosis?

Halitosis is an unpleasant odour emanating from the oral cavity, and it can significantly impact your quality of life, relationships, and self-confidence. While many assume bad breath stems solely from poor oral hygiene, the reality is far more complex.

What Causes Bad Breath? Understanding the Root Sources

Oral vs. Extra-Oral Halitosis

Approximately 5% to 9% of halitosis originates from non-oral structures such as the respiratory and gastrointestinal tract, while the majority begins in the mouth. However, when dental hygiene doesn’t resolve the problem, it’s time to look deeper—specifically at your gut.

Halitosis affects approximately 20% to 50% of adult or adolescent individuals worldwide, making it a common concern that deserves proper investigation.

The Science Behind Bad Breath: Volatile Sulfur Compounds

The characteristic odour of bad breath comes from volatile sulfur compounds (VSCs) produced by bacteria. The oral cavity contains 500 to 700 bacterial species, most of which can produce malodorous compounds that contribute to unpleasant breath.

The primary compounds associated with halitosis include:

  • Hydrogen sulfide (H2S) – related to tongue coating.
  • Methyl mercaptan (CH3SH) – related to systemic alterations.
  • Dimethyl sulfide (DMS) – related to periodontal pockets and gut issues.

The Gut-Breath Connection: Why Your Digestive Health Matters

Your digestive system plays a crucial role in your breath quality. The liver metabolises most gut-derived bacterial metabolites, reducing the “odourant potential” of metabolites. When your gut microbiome is out of balance, it can produce excessive amounts of malodorous compounds that eventually make their way to your lungs and are exhaled as bad breath.

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Gut Dysbiosis and Bad Breath

Unhealthy eating habits and an imbalance of microorganisms in the oral cavity and gastrointestinal tract were identified as primary causes of halitosis. This imbalance, known as dysbiosis, occurs when harmful bacteria outnumber beneficial ones in your digestive system.

In some cases, severe halitosis results from increased formation of malodorous intestinal gases, which can be successfully addressed by targeting gut health rather than just oral hygiene.

H. Pylori Infection: A Hidden Cause of Persistent Bad Breath

One of the most significant gut-related causes of halitosis is infection with Helicobacter pylori (H. pylori), a spiral-shaped bacterium that colonises the stomach lining.

The H. Pylori-Halitosis Link

Research has established a strong connection between H. pylori infection and bad breath:

  • The odds ratio of H. pylori infection in the stomach between halitosis-positive patients and halitosis-negative patients was 4.03, meaning people with bad breath are approximately four times more likely to have H. pylori infection.
  • H. pylori infection was detected in 91% of halitosis patients compared to 32% of control subjects without halitosis.
  • Prior to treatment, halitosis was present in 61.5% of patients with H. pylori-positive non-ulcer dyspepsia.

How H. Pylori Causes Bad Breath

H. pylori is a spiral, microaerophilic, gram-negative bacterium identified as the most frequent cause of gastritis and is believed to be responsible for peptic ulcer and gastric cancer. The bacterium produces volatile sulfur compounds that can contribute to breath odour.

Importantly, since H. pylori infection has no specific symptom, the bacterium may colonise the gastrointestinal tract and cause more serious problems, and in this situation, halitosis may be the only symptom.

Treating H. Pylori Can Eliminate Bad Breath

The good news is that addressing H. pylori infection can resolve halitosis:

  • In a study of 58 dyspeptic patients with bad breath, eradication therapy reduced sulfide levels below the cutoff value in 15 out of 19 successfully treated patients.
  • Among patients with confirmed H. pylori eradication, the most successfully resolved symptoms were halitosis and hunger-like pain.
  • In patients where H. pylori positivity persisted after initial treatment, halitosis parameters did not change, but objective halitosis disappeared after successful eradication by triple therapy.

SIBO: Small Intestinal Bacterial Overgrowth and Bad Breath

Small Intestine Bacterial Overgrowth (SIBO) is another significant gut condition that can cause persistent halitosis. SIBO occurs when bacteria that normally live in the large intestine migrate to and overgrow in the small intestine.

The SIBO-Halitosis Connection

Recent research has revealed striking findings about SIBO and bad breath:

  • The SIBO positivity rate in idiopathic halitosis patients was significantly higher than in healthy controls—74.69% compared to 3.03%.
  • Extra-oral halitosis is closely associated with functional dyspepsia and SIBO, with dimethyl sulfide (DMS) as the primary contributing volatile sulfur compound.
  • Extra-oral halitosis in inflammatory bowel disease occurs when overgrown bacteria in the small intestine produce copious amounts of malodorous volatile sulfur compounds that are absorbed into the bloodstream, carried to the lungs, and exhaled.

SIBO Treatment Success for Bad Breath

The research on treating SIBO to eliminate halitosis is highly encouraging:

  • After probiotic treatment, 87.60% of SIBO-positive patients experienced improved halitosis, a rate significantly higher than observed in SIBO-negative patients (2.75%).
  • Among patients who became SIBO-negative after treatment, 98.97% experienced improved halitosis compared to 41.67% of those who remained SIBO-positive.
  • In patients with metabolic dysfunction-associated steatotic liver disease and extra-oral halitosis, 65.41% were SIBO-positive, suggesting SIBO is a common underlying factor.

How To Get Rid Of Bad Breath: Effective Treatment Strategies

1. Get Tested for Gut-Related Causes

If you have persistent bad breath that doesn’t respond to oral hygiene measures, consider testing for:

  • H. pylori infection: Testing can be done through breath tests, stool antigen tests, or endoscopy with biopsy.
  • SIBO: Diagnosed through hydrogen breath testing that measures gas levels after consuming a sugar solution.
  • Gut microbiome analysis: Comprehensive testing can identify dysbiosis and bacterial imbalances.

2. Address H. Pylori Infection

Halitosis is a frequent but treatable symptom of H. pylori-positive non-ulcer dyspepsia and may be a valid indication for eradication therapy.

H. pylori eradication typically involves:

  • Combination antibiotic therapy (triple or quadruple therapy).
  • Proton pump inhibitors to reduce stomach acid.
  • Follow-up testing to confirm eradication.

However, there are many natural agents, including specific strains of probiotic, that have demonstrated efficacy in eradicating H. Pylori.

3. Treat SIBO with Probiotics and Targeted Therapy

Research found that probiotic treatment effectively improved idiopathic halitosis, probably through its impact on SIBO.

SIBO treatment approaches include:

  • Antibiotic therapy: Targeted antibiotics or antibacterial herbs to reduce bacterial overgrowth.
  • Probiotic supplementation: Beneficial bacteria to restore gut balance. The probiotic L. Reuteri DSM 17938 has been shown to lower methane gas, while probiotics such as S. Boulardii or L. Rhamnosus GG may improve symptoms of hydrogen dominant SIBO.
  • Dietary modifications: Low FODMAP or specific carbohydrate diets may help reduce bacterial fermentation.
  • Prebiotic supplementation: PHGG has actually been shown to improve the efficacy of antibiotics when treating SIBO.

4. Support Your Gut Microbiome

Enhancing oral hygiene habits, using antimicrobial drugs, or administering probiotics may help regulate oral or intestinal flora, thereby improving halitosis and overall oral health.

To maintain a healthy gut microbiome:

  • Eat a diverse range of plant-based foods rich in fiber.
  • Include fermented foods like yogurt, kefir, and sauerkraut.
  • Limit processed foods, sugar, and artificial sweeteners.
  • Stay hydrated to support digestion and elimination.
  • Manage stress, which can disrupt gut bacteria balance.

5. Don’t Neglect Oral Hygiene

While gut health is crucial, oral hygiene remains important:

  • Brush teeth twice daily with toothpaste. I recommend hydroxyapatite toothpaste.
  • Floss daily to remove food particles and plaque.
  • Clean your tongue, as bacteria accumulate on the tongue coating. I recommend the probiotic Bio.Me Oral which has been designed specifically for the oral microbiome.
  • Stay hydrated to maintain saliva production.
  • Visit your dentist regularly for professional cleanings.

6. Consider Specialised Interventions

Management of bacterial malodour may be achieved by controlling the diet and physical elimination of bacteria and accumulated odourants.

Additional strategies include:

  • Zinc supplementation: May help neutralise sulfur compounds.
  • Mouthwash: Effective when halitosis is purely oral in origin.
  • Dietary adjustments: Identifying and eliminating trigger foods.
  • Digestive enzymes: May improve nutrient absorption and reduce fermentation.

When to See a Healthcare Provider

Patient complaints of unpleasant body smell or breath odour require ruling out life-threatening diseases such as diabetes mellitus or liver failure.

Consult a healthcare provider if you experience:

  • Persistent bad breath despite good oral hygiene.
  • Digestive symptoms like bloating, gas, or abdominal pain.
  • Unexplained weight loss or fatigue.
  • Symptoms of gastritis or peptic ulcer.
  • A fruity smell to your breath (may indicate diabetes).

The Bottom Line: Treating Bad Breath from the Inside Out

Bad breath is often more than just an oral hygiene issue—it can be a window into your gut health. Halitosis is a multifactorial condition with various underlying causes, including oral and systemic diseases.

By understanding the connection between your gut microbiome and breath odour, you can take targeted action to address the root cause rather than just masking symptoms. Whether your halitosis stems from H. pylori infection, SIBO, or general dysbiosis, effective treatments are available.

If traditional oral care hasn’t solved your bad breath problem, it’s time to look deeper. Testing your gut microbiome, screening for H. pylori, and evaluating for SIBO can provide the answers you need to finally achieve lasting fresh breath and improved overall health.

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