There is a tree native to Australia called the Tea tree, and an essential oil distilled from its leaves and stems appears to have a myriad of healthful uses - one of them is Tea tree oil for bad breath. It seems that people are using dental floss soaked in Tea tree oil, or adding a couple of drops to the toothpaste on a toothbrush. They say it works wonders.
If you have bad breath Tea tree oil may work because it has antibacterial properties, and the majority of cases of bad breath, particularly the nasty chronic kind, are caused by the activities of bacteria in our mouths. These bacteria break down proteins and produce bad smelling volatile sulfur compounds that are expelled in the breath. Tea tree oil for bad breath may work because the oil is toxic to the bacteria: they are fragile, and can be killed by drugs and chemicals.
If you do some research on Tea tree oil for bad breath, you will discover that the oil should not be taken internally - it is really not known what effect ingesting the oil may have, but it could be toxic. For cleaning the mouth and treating bad breath Tea tree oil should be used topically only - that is, you can apply small amounts to your teeth, but don't swallow! After brushing or flossing, spit out whatever is in your mouth, and rinse.
It should not be a problem to avoid swallowing any significant amount of the oil when you use Tea tree oil for bad breath because, as you probably know, you should not be swallowing toothpaste either (this is particularly important for children). Most municipalities add fluoride to drinking water to reduce tooth decay in the population, and ingesting toothpaste with fluoride in it would result in too much fluoride in the diet. Fluoride added to toothpaste is meant to be applied to the enamel on the teeth and not swallowed; when used for bad breath Tea tree oil is the same.
In the end, if you decide not to use Tea tree oil for bad breath because of fears of toxicity, or for any other reason, there are other natural remedies for bad breath on the market that you might be more comfortable with. Investigate the ones that use an olive oil rinse to physically remove bacteria, or an oxidizing agent to kill them. These new approaches to the treatment of halitosis give us more choices than ever before - when it comes to natural remedies for bad breath Tea tree oil is far from the only thing.