Some causes of bad breath or mouth odor are easily addressed, but others may be a symptom of a more serious condition and require a visit to your doctor to determine the cause.
Food
You may find that you have bad breath after eating foods that have a strong smell, such as coffee, garlic, or fish. This happens not only because small food particles can adhere to your teeth or gums, but because the oils in these foods are absorbed in your bloodstream and travel to your lungs, according to the Mayo Clinic.
Tooth Decay
Decay of any kind creates a foul odor, and this includes your teeth. Cavities, impacted teeth or abscessed teeth can all be responsible for bad breath, according to MedlinePlus, a website published by the National Institutes of Health. Decaying food caught between your teeth can cause a foul odor and contributes to tooth decay.
Gum Disease
Just like your teeth, when your gums aren't healthy they can produce an unpleasant mouth odor. Periodontitis, an advanced form of gum disease, is particularly prone to creating foul odors because of small pockets between the gums and teeth that can trap food or bacteria.
Tobacco Use
Smoking or chewing tobacco products can lead to bad breath for several reasons. According to the Mayo Clinic, it increases your odds of developing periodontitis and can also contribute to dry mouth. Both conditions can create a foul mouth odor. The smell of smoke or chewing tobacco can also be unpleasant and create bad breath.
Tonsil Stones
Tonsil stones, also called tonsilloliths, are compact formations that can sometimes develop in the crevices of intact tonsils. These stones are often covered in bacteria that can cause extremely bad breath, according to a study conducted by Okayama University that appeared in the medical journal "Microbes and Infection" in 2006.
Infection
Infections in any of the areas of the body that connect to the mouth can be a source of bad breath. This includes the sinuses, tonsils, throat, lungs, esophagus and mouth.
Disease
Some diseases can cause an unusual or unpleasant breath odor. Untreated diabetes can create fruity-smelling breath. Bowel obstructions can make breath smell like feces. Various forms of cancer as well as organ failures can also contribute to bad breath.
