Halitosis is a term used to describe noticeably unpleasant odors exhaled in breathing. In most cases (85?90%), bad breath originates in the mouth itself. The intensity of bad breath differs during the day, due to eating certain foods (such as garlic, onions, meat, fish, and cheese), obesity, smoking, and alcohol consumption. Since the mouth is exposed to less oxygen and is inactive during the night, the odor is usually worse upon awakening ("morning breath"). Bad breath may be transient, often disappearing following eating, brushing one's teeth, flossing, or rinsing with specialized mouthwash. Bad breath may also be persistent (chronic bad breath), which is a more serious condition, affecting some 25% of the population in varying degrees.