Halitosis: An unpleasant odor from the mouth, commonly referred to as bad breath. Halitosis can be caused by the consumption of certain foods, poor oral hygiene, alcohol or tobacco use, dry mouth, or by certain chronic medical conditions. From Oral Health Resources Bad Breath: See How to Stop ItNatural Ways to Whiten Your TeethGuide to Wisdom Tooth Surgery Featured Centers What Are the Best PsA Treatments for You?Understanding Biologics 10 Things People With Depression Wish You Knew