What Causes Bad Breath? Our Answers Can Help Prevent Halitosis

Could it be your morning coffee, dental hygiene, or an underlying medical condition? These are only a few of the elements responsible for bad breath.

bad breath

Is your breath less than fresh? If the cause of your stinky mouth is straightforward (e.g., cavities, dry mouth, or bacteria on your tongue), the solution is easy.

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There are few things more repugnant than dragon breath, especially when you’re dealing with a “close talker.” Even worse than being stifled by someone’s offensive mouth odor is having it yourself. If you or someone you’re close to (physically or emotionally) suffers from mouth stink, it’s time to find out what causes bad breath so you can treat it.

For some, bad breath could indicate a more serious medical issue such as diabetes, kidney disease, or liver disease. Others may need only to cut down on coffee or spicy curries. Finding the cause of your bad breath, or halitosis (i.e., chronic bad breath), could help eliminate offensive mouth odor and an underlying disease. (See also our post Halitosis Remedies: 14 Ways to Keep Dragon Breath at Bay.)

What Causes Bad Breath?

All bad breath is caused by bacteria, which generally causes a short-term problem that can be easily fixed. In the case of halitosis, the bacteria contribute to a long-term problem.

First, you need to figure out which type of germ is causing problems (e.g., bacteria caused by fermenting food particles or an overgrowth resulting from decreased saliva). Then you can get to work on ridding yourself of dragon breath.

Your best detective? A dentist who will look at the whole picture, says Dr. Tyrone Rodriguez, spokesperson for the American Dental Association (ADA) and a board-certified pediatric dentist in Central Washington State.

Think of your mouth as a house, he says. “The mouth would be the first floor, the sinus cavities and nasal cavities would be the attic, and the stomach would be the basement. When you want to see why the house is smelling, you sometimes have to look in all three places.”

The First Floor (mouth)Cavities, gum disease, periodontal disease, dirty dentures, cracked fillings, a virus, or bacteria can all contribute to bad breath.
The Attic (nasal and sinus cavities)“Sometimes people have quite a bit of secretion in their nose because of allergies or chronic sinus infections,” Rodriguez says. Others (i.e. young children) may have a foreign object stuck up their nose, all of which may contribute to bad breath.
The Basement (stomach)Digestive problems can cause bad breath. Conditions such as acid reflux, along with high protein diets (i.e. the Atkins diet), and a large consumption of fried foods are also major contributors.
The Housekeeper (saliva)“[Saliva] keeps things kind of rinsed and cleaned off…when we have medical conditions or medications that slow down the production of saliva,” says Rodriguez. Without enough saliva, he explains, our mouths remain dry and “things tend to grow easier, and debris and residue tends to stick around longer, and that can be very contributory to bad breath.”

What Causes Bad Breath Today?

In the past, the two most common causes of bad breath were alcohol (mainly the kind found in mouthwash) and smoking, says Rodriguez. Alcohol is a diuretic, so it will leave your mouth dry. The result: a reduction in saliva, which is essential to neutralizing acid and keeping your mouth fresh and clean.

Today there’s been a shift in causal factors, Rodriguez explains. Alcohol-containing mouthwash has been usurped by marijuana use and vaping in terms of what causes bad breath. “These new social trends are causing bad breath and health issues in a different way,” he says.

Today, The Most Common Causes of Bad Breath Include:

  • Marijuana use
  • Vaping
  • Smoking
  • Eating spicy, onion-laden, or garlic-rich foods
  • Drinking coffee or alcohol
  • Dry mouth (this can be caused by medications, medical conditions, dehydration, and smoking)
  • Being overweight

The Atkins diet, which encourages people to increase protein and reduce carbohydrates during meals, can contribute to bad breath, says Rodriguez. The reason? Proteins contain high amounts of sulfur (the same compound responsible for that putrid smell of eggs). The process of breaking down sulfur can create bad breath.

Medical Conditions That Can Cause Bad Breath Include:

How to Get Rid of Bad Breath

Is your breath less than fresh? If the cause of your stinky mouth is straightforward (e.g., cavities, dry mouth, or bacteria on your tongue), the solution is easy. Drink more water. Also, brush, floss, and rinse every day. Extra points for doing so at least twice! Another tip: brush or scrape your tongue daily, especially the back, which is a breeding ground for bacteria, says Rodriguez. If your tongue isn’t pink, it’s not healthy.

Other fresher breath solutions include: cutting back on sugar and alcohol, drinking more water, chewing sugar free gum, altering your diet to include less spicy, garlicky and fried foods, and swishing with alcohol-free mouthwash.

For more tips, check out 7 Bad Breath Remedies.


Certain foods taint your breath more than others. Once they’ve been digested, their odor is released to the lungs and then exhaled, which occurs about two to three hours after you eat. A few of the worst offenders include:

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Shandley McMurray

Shandley McMurray has written several of Belvoir’s special health reports on topics including stress & anxiety, coronary artery disease, healthy eyes and pain management. Shandley also has authored numerous articles … Read More

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