25

Percentage of adults worldwide affected by chronic halitosis, or bad breath, most of which is caused by oral bacteria’s breaking down proteins and producing volatile sulfur compounds that coat the tongue

615

Number of bacteria species that researchers at the Harvard School of Dental Medicine counted in the human mouth

15

Percentage of halitosis cases that originate somewhere other than the mouth, as the result, for instance, of sinus infections, diabetes, kidney failure and metabolic disorders (about 19)

5

Highest number on the organoleptic scale (for which trained experts sniff and rate a person’s breath), denoting “extremely foul odor”

25–34

Age range during which the incidence of halitosis is greatest, according to a study, published in 2005, of patients at the Department of Conservative Dentistry in Warsaw, Poland

6.7 billion

Dollars spent in 2007 on mouth-freshening products in the United States

10

Number of questions on a survey created to assess a halitosis patient’s psychological state; patients who complain of bad breath but have no detectable halitosis could be suffering from pseudo-halitosis (imagined halitosis) or halitophobia (an obsessive-compulsive disorder)

10

Percentage of people who would inform a friend or family member if he or she had persistent bad breath, according to a recent poll of 1,500 patients at a dental practice in Cheshire, England