Review of Local and Systemic Factors Contributing to Halitosis: A Narrative Review

Abstract

Introduction: Halitosis, or oral malodor, is a common health and social problem that can negatively affect interpersonal relationships, self-confidence, and quality of life, and in many cases may indicate the presence of local or systemic disorders. This narrative review aimed to examine the etiological factors, diagnostic methods, clinical significance, and strategies for the prevention and treatment of halitosis.

Methods: In this narrative review, the databases PubMed, Google Scholar, Scopus, and Web of Science were searched using the keywords "Halitosis," "Oral Malodor," "Etiology," and "Treatment" for publications from 2003 to 2025. Relevant articles were screened by title, abstract, and full text, and ultimately 28 scientific sources were included, reviewed, and their findings were analyzed descriptively.

Results: The findings showed that approximately 80–90% of halitosis cases originate from local intraoral factors. Poor oral hygiene, periodontal diseases, dental caries, dental calculus, coated tongue, and diseases of the nose, sinuses, and pharynx are the most important local causes. Some systemic conditions, including diabetes mellitus, chronic renal failure, liver cirrhosis, lower respiratory tract disorders, and possibly certain gastrointestinal disorders, may also contribute to oral malodor. Non-pathological factors such as tobacco use, xerostomia, pregnancy, puberty, menstruation, and fasting can also play a role.

Conclusion: Halitosis predominantly originates from local oral factors and can be effectively controlled and prevented through proper oral hygiene practices, timely identification of underlying causes, and appropriate management of related diseases.