Bacteria is the leading cause of bad breath, or halitosis as it is known in medical terms. Since bacteria is always present in the mouth, preventing bad breath from emerging needs ritual dental health care and vigilance. Balancing the bacteria in the mouth plays an essential role in preventing bad breath. There are factors, however, that can put you at more risk of developing gum disease. Bad breath can be caused by dry mouth, or xerostomia. Saliva is the first line of defense in controlling bacteria population, thus avoiding dehydration and dry mouth can prevent bad breath. Diseases such as gum disease or other health complications can also contribute to halitosis. Constant bad breath, or chronic halitosis, can be due to various reasons. Keeping a log of your medication and food intake is helpful in understanding the cause of the bad breath problem. By eliminating the true source of the bad breath is due, you can stop the problem from coming back.