What are the causes of halitosis (bad breath)?

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From the Guidelines

Halitosis is primarily caused by poor oral hygiene, allowing bacteria to grow in the mouth and produce sulfur compounds that create unpleasant odors, and can be addressed through thorough oral hygiene practices and potentially treated with natural products such as those containing anti-bacterial, anti-inflammatory, and anti-oxidant properties 1. The main causes of halitosis include:

  • Food particles trapped between teeth
  • Bacterial growth on the tongue
  • Gum disease
  • Dry mouth (xerostomia)
  • Tobacco use
  • Certain foods like garlic and onions
  • Medical conditions such as sinus infections, postnasal drip, acid reflux, diabetes, liver or kidney problems, and some medications that reduce saliva production To address halitosis, it is recommended to:
  • Maintain thorough oral hygiene by brushing teeth twice daily with fluoride toothpaste
  • Floss daily
  • Clean the tongue with a tongue scraper
  • Use an antimicrobial mouthwash
  • Stay hydrated
  • Avoid tobacco products
  • Consider using natural products such as herbal-based mouthwashes or toothpastes that have anti-bacterial, anti-inflammatory, and anti-oxidant properties, as discussed in recent studies 1. If halitosis persists despite good oral hygiene, it is essential to consult a dentist to rule out gum disease or a physician to investigate potential underlying medical conditions. Regular dental check-ups every six months can help prevent many causes of bad breath through professional cleaning and early detection of oral health issues.

From the Research

Causes of Halitosis

  • Halitosis is primarily caused by bacterial putrefaction and the generation of volatile sulfur compounds 2
  • Oral causes of halitosis include:
    • Poor oral hygiene
    • Periodontal disease
    • Tongue coat
    • Food impaction
    • Unclean dentures
    • Faulty restorations
    • Oral carcinomas
    • Throat infections 2
  • Systemic causes of halitosis include:
    • Renal or hepatic failure
    • Carcinomas
    • Diabetes
    • Trimethylaminuria 2
  • Other causes of halitosis include:
    • Certain foods
    • Dry mouth
    • Tobacco products
    • Medical conditions 3
  • It is estimated that 85% of halitosis cases are related to oral causes, while 10% are related to systemic causes 2
  • In some cases, halitosis can be caused by respiratory tract conditions such as sinusitis, tonsillitis, and bronchiectasis 4

Prevalence of Halitosis

  • The prevalence of halitosis varies, with some studies reporting rates ranging from 22% to over 50% 3
  • Halitosis can have a significant impact on a person's social interactions and quality of life 5

Etiological Factors

  • The etiological factors of halitosis include the microbial degradation of oral organic substrates, including volatile sulfur compounds (VSC) 3
  • The reduction of the intraoral bacterial load and/or the conversion of VSC to nonvolatile substrates is important in the treatment of halitosis 3

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Halitosis. A common oral problem.

The New York state dental journal, 1996

Research

Halitosis.

BMJ clinical evidence, 2014

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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