Bad breath, or halitosis, afflicts most of us at some point or another. If your friends have told you that you have bad breath often (and you know that they are friends if they tell you, because it's often difficult to detect bad breath ourselves), rather than rely on gums, mints, and mouthwashes that are primarily flavored alcohol, there are things you can do about it.
First, see your dentist. Most halitosis (80-90%) is caused by a buildup of plaque (bacteria that naturally form in the mouth) or by bits of decaying food that have been left between the teeth by improper cleaning. But, in some cases halitosis can be caused by more serious dental problems, such as gingivitis, undiagnosed cavities or gum disease, so it's best to rule them out.
If there seem to be no dental or systemic issues causing the bad breath, the next step is to become more thorough in your cleaning; a dirty mouth is a smelly mouth. Brush and floss at least twice a day, and consider using a toothpaste that contains tea-tree oil, a natural disinfectant. When you brush, be sure to also brush or scrape your tongue, which can become coated with odor-causing bacteria. If you wear dentures, remove them at night and clean them.
During the day, remember to "wet your whistle." Saliva helps to keep your mouth clean because it is anti-bacterial, and helps to wash away particles of food. Try to avoid things that dry out the mouth, such as alcohol (including the alcohol in commercial mouthwashes) and, interestingly enough, stress. Naturally, avoid foods that commonly are associated with bad breath, such as onions and garlic. Drink lots of water, and use it to rinse your mouth out several times a day. In addition, some of the following suggestions may prove useful:
Snack on fresh fruit and vegetables. Celery, carrots, jicama, and apples are crunchy, and eating them helps to remove bacteria and plaque from your teeth. Low-fat, non-smelly cheeses also are great for snacks, because they fight plaque and mouth odor.
Use herbs and spices to freshen your breath. Rather than throw away that sprig of parsley on your plate at lunch, chew it. Chewing fresh rosemary, tarragon, spearmint, cloves, fennel, or cardamom freshens the breath, as does eating oranges and orange peels. The Vitamin C in the latter also helps to fight bacteria. Cinnamon contains essential oils that can significantly reduce the bacteria in your mouth.
Switch to tea. Both green and black tea contain polyphenols, which are antioxidants that help to prevent plaque from clinging to your teeth, and inhibit the growth of bacteria.
Supplements might help. Magnolia bark extract has been found to kill most bacteria found in the mouth within half an hour. Fish oil supplements aid digestion, and have been shown to reduce oral inflammation and bacteria. Vitamin C can help to prevent gingivitis and gum disease. All are available at your local health food store.