Americans spend about $500 each year to combat halitosis (bad breath). Yet these mouthwashes, sprays and toothpastes simply replace the bad breath with a stronger odor - a cover up that lasts only a short time.

Chronic bad breath affects an estimated 60% of adults (a total of 40 million), a problem that worsens as we age. While medical reasons - sinusitis, emphysema and diabetes, for example - can contribute to halitosis, the major cause comes from what goes on in our mouths.

Offensive foods and tobacco can, at times, be responsible. Yet, if you stop smoking or avoid eating certain foods, the problem should cease. Chronic bad breath, however, won't. It's due to sulphur compounds produced by bacteria in the mouth.

Saliva serves to balance the mouth's acid level, making it an unfriendly place for bacteria. When we sleep, the saliva flow decreases. This reduction and the drying of the mouth produces "morning breath."

The primary reason for bad breath are conditions in the mouth that allow bacteria to thrive. These include gingivitis and periodontal disease (where bacteria also destroys bone); the tongue's coatings; and faculty dental work, dentures and moved, drifted or extracted teeth.

To dislodge bacteria from under the gums, regular flossing and brushing will help. Proper hand brushing needs to be performed at least five minutes twice a day - although this time-consuming task has been greatly reduced with the use of the ultrasonic toothbrush.

A tongue scraper can also prove helpful in removing the many layers of tongue coatings that protect the bacteria. While mouthwashes inhibit the growth of bacteria, their alcohol content has a drying effect on the mouth's tissues (an underlying cause of bad breath). Certain brands of toothpaste push their ability to freshen breath, yet none eliminates bacteria and the sulphur compounds that cause bad breath.