Causes of Bad Breath

causes of bad breath

When it comes to having a great smile, many people place emphasis on the look of their smile, as well as the absence of bad breath. Unfortunately, even a beautiful smile can be partially ruined when accompanied by a foul stench and the American Dental Association reports that 50% of Americans have had bad breath at some point during their lives. For these reasons, many people are concerned about what causes bad breath and how to get rid of it as quickly as possible. 

Although most people are more concerned about getting rid of bad breath fast instead of what causes it, knowing the cause is actually the best way to eliminate bad breath. You see, there are certain causes of bad breath that may need to be managed in a particular way to eliminate harsh odors. Therefore, determining the cause of your bad breath is the first step to getting rid of it. Here are some common causes of bad breath: 

Poor Oral Hygiene

plaque and bacteria along the gumline

To properly clean your teeth and keep your breath smelling fresh, the American Dental Association recommends brushing your teeth twice a day for two minutes and to floss daily around each tooth. Unfortunately, not everyone adheres to this routine and some may even have trouble reaching all the areas in the mouth in need of cleaning. Missing places or not adhering to recommended hygiene practices increases the likelihood that you have bacteria accumulating somewhere inside your mouth. As bacteria accumulate, this can cause a foul odor to form inside your mouth. 

One unfortunate consequence of poor oral hygiene is gum disease, which is the inflammation of the gum tissue caused by excess bacteria growth. You see, when plaque is not removed with proper brushing and flossing, it will continue to accumulate and collect bacteria until it hardens into tartar. Tartar is hardened to the tooth and can create tiny pockets that sit between the teeth and gums, collecting even more bacteria. If you have any symptoms of gum disease, it is important to schedule an appointment as soon as possible.


Sometimes, bad breath can also be caused by certain foods and beverages. Take onions and garlic for instance. Both contain an oil that is absorbed by the stomach into the body. Once absorbed, this oil passes through the lungs and alters the way your breath smells for up to 72 hours. Other foods and beverages with strong scents can have a similar effect, which temporarily alters the way your breath smells. To reduce bad breath after eating or drinking, try rinsing, brushing, or using mints afterwards to cleanse your mouth. 

woman with stained teeth smoking a cigarette


Just like foods and beverages with strong scents can affect the way your breath smells, so can cigarettes. Not only does the taste and odor of cigarettes make your breath smell bad, but smoking also causes dry mouth, which is another factor that contributes to bad breath. 

Dry Mouth

Your mouth uses saliva to help keep itself clean. However, individuals with dry mouth are not able to produce adequate amounts of saliva. This means that it is easier for bacteria to grow and remain in the mouth. The more bacteria present, the stronger the odor. To combat bad breath caused by dry mouth, you will want to take additional steps to keep your mouth as moist as possible. Drinking water frequently, chewing gum, or sucking on sugarless candies are all ways to help produce saliva and decrease bad breath associated with dry mouth. In some cases, dry mouth can also be a side effect of certain medications, so changing medications can also help relieve symptoms.

Medical Conditions

Bad breath can also occur when you have an infection in your sinuses, nasal passages, tonsils, brochial tubes, or upper/lower respiratory system. In these cases, bad breath is usually temporary and will resolve itself once the infection has been treated. However, there are also other medical conditions such as kidney disease, diabetes, and gastroesophageal reflux disease (GERD) that can cause chronic bad breath. In these cases, the best way to reduce bad breath is to seek treatment for these medical conditions. 

Dr Alina Huang DMD

Dr. Alina Huang has been practicing dentistry in Manhattan for the last eight years. She was born in New York City, and raised in California where she received her Bachelor’s degree at UCLA, and her D.D.S. at the University of the Pacific in San Francisco. She then made her return to NYC where she completed her General Practice Residency at Montefiore Medical Center and has been working in private practice ever since. She continues her learning by attending courses to stay current with the latest advancements in dentistry and refine her skills.