gums & teeth, Health

The Origins of Bad Breath

Why We All Get Bad Breath

We’ve all experienced that late night hanging with friends with increasingly bad breath as the tortilla chips and tequila shots pile up and the night carries on. We are all too familiar with that sour aftertaste after eating a delectable bowl of Frosted Flakes. Why does our breath seem to so deeply love being the party pooper? Why is it so... bad?

Gram-negative bacteria are the stinkers

About 85% of bad breath cases result from oral conditions – the result of smelly compounds excreted by the millions of bacteria feasting on food and dead cell particles in our mouth. You'll be pleased to learn that our mouth has 100-200 bacterial species (and hundreds of millions to hundreds of billions of individual bacteria) inhabiting it at any given time. 

Above the gum line, gram-positive bacteria form the majority of dental plaque – the living film of bacteria and polysaccharides coating your teeth. These species love sugar and secrete acid that can cause cavities, but they are not heavy producers of stinky smelling compounds. 

In contrast, gram-negative bacteria, the smelly species that burrow below the gum line, are much gassier. They thrive in gaps between the gum and tooth and in the crevices of your tongue. These little guys produce gassy smelling volatile sulfuric compounds –the real culprits behind bad breath.

Gram negative bacteria comprise the stinky ones. They love to hang under your gum line, so it's important to floss for fresher breath.

Gram negative bacteria comprise the stinky ones. They love to hang under your gum line, so it's important to floss for fresher breath.

The Stinkers Thrive In Acidic Environments

Our gram negative bacteria – the stinkers – thrive in acidic, oxygen-poor environments. These guys are the real bad breath offenders. In acidic environments (a pH of lower than 7), gram-negative bacteria thrive and displace our oral-health related, pH neutral loving bacterial species. 

The Stinkers Love Dehydration

Our saliva, which is oxygen-rich and pH neutralizing, naturally keeps the growth of our stinky bacteria and bad breath in check. Our stinky bacteria thus LOVE it when we dehydrate ourselves since dehydration reduces our saliva flow (our body's natural defense). Reduced saliva flow usually results in increased acidity (aka lower pH).

Common Ways We Dehydrate Ourselves (And Get Bad Breath)


  • Coffee

    • Caffeine dehydrates our mouth. This dehydrating effect combined with the fermentation of milk or sugar residue in our mouth often contributes to dry, sour breath.

    • If you can't cut back on coffee, just drink plenty of water after you drink coffee to counterbalance dehydration. In fact, if you drink enough water with your coffee, it may be a good thing.  Scientists from Tel Aviv University found that coffee may even inhibit bacteria that lead to bad breath.

  • Alcohol

    • Alcohol really dries out your mouth. The bacteria simply love it.

    • Tips:

      • Have a glass of water for every drink consumed to prevent bad breath.

      • Choose your mouthwash carefully. Many brands contain up to 27% alcohol. When the minty fresh wears off in an hour or so, mouthwashes can leave your mouth drier and more stale.

  • Stuffy nose

    • Colds can force you to breathe through your mouth, which dries out your tissues and reduces saliva flow. With reduced saliva flow your mouth becomes more acidic. The acid-loving, stinky bacteria thrive in this acidic environment and can cause bad breath.

Gram negative bacteria – the stinkers –  love alcohol. Here's why: 1. Alcohol dehydrates you 2. Salivary flow decreases 3. Acidity in your mouth increases 4. Stinkers party and multiply.

Gram negative bacteria – the stinkers –  love alcohol.

Here's why: 1. Alcohol dehydrates you 2. Salivary flow decreases 3. Acidity in your mouth increases 4. Stinkers party and multiply.

The Stinkers Love Sugar

Stinky bacteria have a sweet tooth. When you eat sugary foods, your bacteria feasts on the sugar. They ferment sugar (convert sugar to acid), releasing acids that lower the pH of your mouth. 

Other Possible Causes Of Bad Breath

Bad breath doesn't always come from your mouth.  Other possibilities include, but are not limited to: Medications, diet (garlic, onions), infections, metabolic conditions or disorders.  

Remedies For Bad Breath

Manicure your tongue

Our gram negative bacteria love the dark, moist crevices on our tongue’s surface. Up to 70%+ of the bacteria that cause bad breath live and breed here. You can try gently scraping your tongue with a soft toothbrush or tongue scraper.

Eat fresh

The modern diet is full of sugary processed foods (think of those delicious snickerdoodles, wheat thins, Joe Joes, etc.). Two bad breath causing things happen when we eat processed foods.

First, we chew less so there is less friction to dislodge bacteria in the digestion process and less salivary flow.

Second, bacteria love the processed sugar. As bacteria ferment the sugars in your mouth, they release acids and volatile sulfuric compounds (think garlic, fish, rotten eggs). For instance, recall that sour taste in your mouth after eating a bowl of cereal or a doughnut? 

Replace processed foods with fresh fruit, proteins and vegetables and you should notice a significant difference in your breath quality.

Eat yogurt

In a study performed by the International Association for Dental Research, those who ate yogurt twice a day for six weeks saw an 80% drop in the levels of hydrogen sulphide — a major cause of bad breath.

Drink more water

Staying hydrated helps us maintain optimal salivary flow. Water also helps neutralize the pH to keep stinky bacterial colonies (that love acidic environments) and bad breath in check. 


Mouthwashes work via one (or both) of the following mechanisms to mask or neutralize bad breath:

  • Mask odors:

    • Most mouthwashes do not improve oral ecology, but contain compounds that help mask unpleasant odors. 

  • Carpet bombing:

    • Mouthwashes, such as those containing chlorhexidine, target and kill all bacteria. While carpet bombing isn’t the ideal approach since it kills the good and bad bacteria alike (essentially reducing bacterial counts – the good and the bad), it can temporarily reduce bad breath. A number of researchers are working on more ideal alternatives to specifically target the stinkers.

Oil pulling

Oil pulling is a folk remedy that originated in India. It first appeared in an early text of Ayurvedic medicine (aka Indian traditional medicine). Via this technique, you are advised to gargle one tablespoon of oil (coconut, sesame, sunflower etc.) for 20 minutes once per day.

Practicers of oil pulling have noted fresher breath amongst a myriad of additional, purported benefits. It's believed that the swishing action of oil pulling may loosen bacteria via a soap-like mechanism and that the medium chain fatty acids in coconut oil may inhibit bacterial growth.


The stinkers love to hide out in between your teeth, along your gum line, and on your tongue. If you don’t believe it (and if you dare), try taking a whiff of your floss after using it.  Don’t let the bacteria party in your mouth! Floss daily to beat bad breath!


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