Halitosis Causes: Poor Hygiene, Dry Mouth, Diet, Medical Conditions, and More

Bad breath (halitosis) affects ~25–30% of people. Most causes are oral; some are systemic.

Oral Causes (85–90%)

• Poor oral hygiene: Plaque, food debris → bacterial putrefaction → volatile sulfur compounds (VSCs: H₂S, CH₃SH, (CH₃)₂S).
• Tongue coating: Posterior dorsum — major VSC source.
• Periodontal disease: Deep pockets harbor anaerobes.
• Dental caries, faulty restorations, food traps.
• Dry mouth (xerostomia): ↓ saliva → ↓ clearance, ↑ bacteria. Causes: medications (anticholinergics, diuretics), Sjögren's, mouth breathing, CPAP.
• Dentures: Poor cleaning, overnight wear.

Dietary Causes

• Alliums (garlic, onions) — sulfur compounds absorbed → exhaled via lungs.
• Spices, cruciferous vegetables, alcohol, coffee.

Systemic/Medical Causes

• ENT: Tonsilloliths (tonsil stones), chronic sinusitis, post-nasal drip, foreign body.
• Respiratory: Bronchiectasis, lung abscess.
• GI: GERD (acid reflux), H. pylori, Zenker's diverticulum.
• Metabolic: Diabetes (ketones — fruity), uremia (ammonia), liver failure (fetor hepaticus).
• Medications: Nitrates, chemotherapy, some antidepressants → dry mouth or metabolic byproducts.

Diagnosis

• Organoleptic assessment (gold standard).
• Halimeter (VSC measurement).
• BANA test (periodontal pathogens).
• Gas chromatography (research).

Management

• Tongue scraping (most effective single step).
• Flossing + brushing 2×/day.
• Hydration, sugar-free gum (xylitol) for salivary flow.
• Treat periodontal disease, caries.
• Address medical causes.
• Chlorhexidine/CPC rinses (short-term).

Persistent halitosis despite oral hygiene warrants dental/medical evaluation.