What Causes Bad Breath: From Diagnosis to Treatment

If there’s one thing that absolutely no one likes, that’s bad breath and tolerating bad breath is simply not an option. People can have bad breath due to several reasons. If it isn’t the oniony or garlicky breath that will subside after a few hours (or days if you really feasted on these ingredients), it is a cause for alarm. Bad breath might indicate an underlying medical condition or oral health issue. In order to understand that, you need to find out what causes bad breath. 

There’s no singular reason for bad breath. No matter what, constant bad breath makes it difficult for anyone to have a normal life. When conversing with a friend, colleague, or family member, you have to maintain a certain distance. Of course, no one wants to be known for their bad breath, and trying to keep a certain distance from everyone can have a huge impact on your social, love, and even business life. That’s why finding out what causes bad breath is more than just important. But first, here’s something interesting you should know.

The Bad Breath Paradox

According to one study, 25% of the population has halitosis or bad breath. In 85% of the cases, the problem lies in the oral cavity. Only people with halitosis sometimes really don’t know that their breath smells bad. You might think that the other person is choosing to ignore this issue and continue with their life, but that’s not always the case. 

One study that appeared in the Journal of the American Dental Association found that the way the participants rated their breath was according to their preconceived notions. In other words, even if participants knew how to detect bad breath, their perception of what a “bad breath” is, affected their ability to judge how their own breath should smell.

There’s also such a thing as “halitophobia,” where a person has an extreme fear of bad breath even when they don’t have a bad breath. It is possible for someone to develop halitophobia after they have halitosis. The fear persists even after the bad breath is treated. People can also develop halitophobia after someone points out their bad breath to them. Since it’s not a dental condition, the treatment for halitophobia can involve therapy.

What Causes Bad Breath? 

Onion or garlic may not always be responsible for your bad breath. There are more than a few reasons why you may have bad breath. 

Poor Oral Health 

Brush twice and floss once a day. It’ll make sure that the food particles that are stuck between your teeth get out. If the food remains stuck, it can lead to the build-up of plaque. It can also cause cavities and gum disease, which can itself become a cause of bad breath. When cleaning your mouth, don’t forget the tongue. The uneven surface of the tongue can also trap food particles. `

Drying & Acidic Foods

By eating a lot of citrus foods, you might not be doing a favour to your mouth. The bacteria that are responsible for producing bad odour thrive in acidic environments. Surprisingly, a high-protein diet can also give you bad breath (a high-protein keto diet causes the keto breath). The breakdown of protein produces ammonia; that comes out of the body through the mouth (it may smell like cat pee).

The amino acids in the cheese, together with the oral bacteria, produce sulfur compounds. Drinking coffee can make the mouth dry. Less saliva led to an increase in the number of bacteria that produce a foul smell. Drinking alcohol has the same effect. It can cause a decrease in the production of saliva. A dry mouth means more odour-causing bacteria. 

Eating foods high in sugar is probably not a great idea either. Now, the sweets may smell and taste nice to you, but the bacteria in your mouth will consume those sweets and produce bad smells. Eating healthy and balanced is a great option for anyone who wants to prevent bad odour.


One of the most common answers to what causes bad breath is smoking. If you smoke cigarettes or any other tobacco product, it is definitely going to make your mouth smell. There’s no wondering what causes bad breath here. The chemicals in the smoke will linger in your mouth and lungs, which will make your mouth smell even when you’re not smoking.

The smell gets trapped in the lungs. And mouthwashes won’t help it. Hence the smoker’s breath. However, that’s not the only way your mouth suffers. Smoking can cause countless other oral health issues such as tooth decay, gum diseases, and oral cancer. 

Dry Mouth 

A condition known as xerostomia can cause a decrease in the production of saliva. It is not a disease and can happen due to different reasons. Some medicines can make the mouth go dry. It can also happen due to ageing or due to radiation therapy to the head and neck. The latter can affect the salivary glands and can be the answer to what causes bad breath for you. 

Dentures and Braces 

With braces, food particles can easily get stuck between the teeth and even in the hardware of the braces. The food is broken by the bacteria then causes bad breath. Improper cleaning of the dentures can make them smell. It can also cause infections in the mouth which can also make your mouth smell. 

Morning Breath 

Well, there’s not much you can do about that. When you’re sleeping, your mouth gets dry, and the bacteria again thrive in such environments. Just make sure to brush your teeth at night, floss, and use mouthwash before sleeping, so that the smell is not too bad in the morning.

Common Cold

You might’ve noticed that after catching a cold, your breath starts to smell bad (or worse). Because the nose is clogged, you’re likely to breathe from the mouth, which dries it out. In addition, all the mucus has a bad smell, and bacteria even feed on them. So, when it comes to a common cold, the answer to what causes bad breath is – many things.

What Causes Bad Breath From the Stomach?

When it comes to answering, what causes bad breath, you should not disregard the stomach itself. After all, that’s where the food goes. Normally, your stomach should not give you bad breath. However, that may not be the case if you have gastroesophageal reflux disease or GERD. The undigested food in the stomach, mixed with acids and microorganisms, regurgitates. It can leave a bitter taste in the mouth, and you can end up with a bad breath.

How Do You Know If Your Breath Smells Bad? 

People with halitosis might not even know that they have bad breath, so how exactly do they find out if they have this problem? There are a few things that you can do about this:

  • Ask someone you know: You can ask a friend or family member to smell your breath. Although, understandably, not everyone is comfortable with this.
  • Licking: You can lick your wrist and smell it after the saliva dries. If it smells, there might be a problem.
  • Tongue scraping: You can also try using a tongue scraper. After scrapping, take it out, and smell it to find out if you have bad breath. 
  • Visit your dentist: You can also simply go to the dentist and find out if you have bad breath. They might use a Halimeter to quantify the degree of bad breath that you have. The device measures parts-per-billion (ppb) of the compounds that are responsible for producing bad breath. 

According to a study published in the Journal of Neurogastroenterology and Motility (JNM), bacteria at the back of the tongue are responsible for bad breath. They produce volatile sulfur compounds (VSCs). If the Halimeter’s measurement is above 100 ppb, it indicates bad breath. 

There are other tests available to diagnose halitosis. Gas chromatography also measures VSCs to determine if a person has halitosis. Some tests find out the level of certain enzymes in the mouth that are associated with bad mouth odour or halitosis. 

How To Get Rid of Bad Breath Permanently? 

Now that you know the answer to what causes bad breath, let’s take a look at some of the treatments that are available for it. If the cause of the bad breath is plaque buildup, a dental cleaning can help. However, if the bad odour is a result of gum disease, you might need gum treatment. The problem might not always be with oral health.

Chronic bad breath that doesn’t go away with proper oral hygiene might indicate an underlying health condition. Get in touch with a doctor to get yourself checked. Kidney disease or sinus infection can also give you bad breath. In this case, the bad breath will linger until the underlying health condition gets treated. 

How Can You Prevent Bad Breath? 

Instead of trying to find the answer to what causes bad breath, you can consider doing the following to prevent it:

  • Make sure to brush your teeth, but brushing alone is not enough. The bristles cannot reach the area between your teeth, which is why flossing is important.
  • Include an antimicrobial mouthwash in your routine. The bacteria in the spaces between the teeth can also produce a bad smell.
  • Quit smoking to get rid of your smoker’s breath.
  • Drink water and stay hydrated so that your mouth doesn’t get too dry.
  • Get a dental cleaning twice a year after every 6 months.

These things can help keep the bad breath at bay and not keep you wondering about what causes bad breath.

Summing Up the Discussion 

Bad breath is something that many people struggle with, even if for a short while. You also know the answer to what causes bad breath. Taking some medicines can dry out the mouth. Morning breath is inescapable. And so is garlic or onions. But even after maintaining proper oral hygiene, the bad smell lingers, you should get in touch with a dental professional.

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