Although halitosis is generally thought of as a social handicap related to poor oral hygiene or disease of the oral cavity, it may also indicate a serious systemic illness that requires diagnosis and treatment. Halitosis can be the result of pathologic or nonpathologic factors, both local systemic. A complete physical examination, with laboratory and radiographic studies as indicated by the history and physical examination, will generally identify a treatable cause for halitosis. Treatment is directed at the underlying cause. Simple measures, including careful oral hygiene, may be employed to lessen breath odor.