7 Common Causes of Bad Breath That Are Often Unnoticed

Bad breath is a fairly common problem experienced by many people. This condition can even undermine a person’s confidence when talking to others.

A general and cosmetic dentist from Arizona, United States, Dr Jossen Gastelum, says that bad breath often originates from bacteria that thrive in the mouth.

“There are many factors that can cause bad breath, ranging from the foods consumed to the bacteria in the mouth and the digestive system,” Dr. Gastelum explained, as reported by Prevention on Saturday 23 May 2026.

He explained that, in many cases, the unpleasant odour arises from sulphur compounds produced by bacteria in the mouth. Here are several common causes of bad breath to watch out for.

Food particles left between teeth and on the tongue can become breeding grounds for bacteria. The longer they are left, the bacteria will produce unpleasant odour.

Los Angeles-based dentist Dr. Ilona Casellini explained that irregular brushing and flossing can worsen this condition.

“Not brushing teeth and cleaning interdental spaces regularly leaves food particles in the mouth, thereby encouraging bacterial growth,” Dr. Casellini said.

She added that the bacteria produce sulphur compounds that are the source of bad breath.

Additionally, a tongue that is seldom cleaned can be coated with a white layer containing bacteria and food debris.

When decayed teeth are not treated promptly, the area becomes an ideal place for bacteria to thrive. A similar thing happens with inflamed or bleeding gums.

In some cases, bad breath due to gum disease is even more pungent and difficult to remove despite brushing.

Dr. Gastelum explained that infections in the oral cavity create an environment that triggers excessive bacterial growth.

Moreover, inflamed tonsils or the presence of tonsil stones can also worsen bad breath because they become a site for the accumulation of dirt and bacteria.