An Ulcer. OK, the ulcer itself may not be the problem. But a type of bacteria that causes ulcers, Helicobacter pylori, can also trigger bad breath, according to a study in the Journal of Medical Microbiology. Treating the bacteria may get rid of the stink.

Can mouth ulcers smell?

Painful mouth ulcers or an unpleasant smell or taste in the mouth are often reasons for a visit to the dentist.

How do you know if your ulcers are bad?

If the dull, burning ache from your ulcer turns into a sharp pain, see your doctor right away. This could mean that the ulcer has caused a more serious problem, like a perforation in the wall of your stomach or intestine, or a blockage in your digestive tract.