Ways to test for bad breath (halitosis).

- Having bad breath is bad enough but not knowing that you do is even worse. This page describes methods you can use to smell your own breath and judge its level of offensiveness, and also some of the tests dentists and dental researchers use to quantify levels of halitosis.

Illustration showing the connection between the mouth and nose.

Odors from your mouth escape to your nose, thus desensitizing its ability to detect them.

How to tell if you have bad breath.


Why testing yourself can be difficult.

Due to the way our bodies are set up and function, it can be tricky for a person to smell, and then judge, the quality of their own breath. Here's why:

  • Our mouth is connected to our nasal area by way of an opening behind the soft palate, thus allowing any smells originating in the mouth to pass directly to the nose.
  • However, our sense of smell tends to ignore background odors, like those coming from the mouth via the pathway just mentioned.

  • That means it's quite possible, and even likely, that a person may have halitosis and not know it, because they literally can't smell their own breath.

So, with self-testing, the trick is to figure out a way around this conundrum.

How to test yourself for bad breath.

What you need to do is create a way where you can evaluate your breath indirectly. You transfer its odor to another object, and then smell that.

Image showing the anterior part of the tongue.

The tip of the tongue is fairly self-cleansing.

Test #1.

  • Lick your wrist.
  • Wait about five seconds to let the saliva dry a little.
  • Now smell it.

Well, what do you think? For better or worse, that's the way you smell. Or, more precisely, that's the way the tip end of your tongue smells (its "anterior" portion).

Did you pass this first test?

If your breath problems are fairly minor, you may not be able to detect much of an odor. (That's because this part of the tongue is relatively self-cleansing.)

Image showing the he posterior part of the tongue.

The back part of the tongue usually harbors debris that is the primary cause of bad breath.

Test #2.

Now, try this second experiment. It will check the odor coming from the back portion of your tongue (its "posterior" region). This part of the tongue isn't as self-cleansing.

  • Take a small spoon out of your silverware drawer.
  • Turn it upside down, place it at the very, very back of your tongue and draw it forward.
  • Be deliberate but gentle. (Don't be surprised if you find you have an active gag reflex.)

Image of spoon full of bacterial debris scraped off a person's tongue.

Smelly debris scraped off the back part of a person's tongue.


Take a look at the gunk you've scraped off. It can be just a clear runny liquid. But often enough it's a thick whitish, yellow or even brown goo.

Generally speaking, the darker the color and thicker the goo, the more likely you're going to discover breath odor.


Now, go ahead and take a whiff. What do you think? Not so bad, or pretty nasty?

[If you want to amplify the smell of the scrapings, close them up in a baggie and then put it somewhere warm (shine the high-intensity lamp on your desk on it). After 10 or 15 minutes, open the bag and take a whiff.]

That's what you smell like to others.

This odor, as opposed to the sampling from the anterior portion of your tongue in test #1, is probably the way your breath smells to other people. And if you haven't been cleaning the back portion of your tongue, it may be pretty foul.

By the way, now you know why you have bad breath.

It just so happens that this second test reveals why most people (and you if you failed it) have breath odor. The most common underlying cause of halitosis is the whitish coating that covers the surface of the posterior portion of a person's tongue.

Another way to perform self-testing.

Here's a variation on the way you can run the test we've outlined above. It's not better, just different. Dentist's sometimes use this method to demonstrate to their patient's what their breath smells like.

  • Get a 2 by 2 inch square of medical gauze, the kind used for bandages.

    [You should be able to find it at any pharmacy. Get just normal gauze (it looks and feels like very loosely woven cloth), not the ouch-less, non-stick variety. Anything larger than 2 by 2 inches is fine too, just cut it down so it fits in your mouth.]

  • Stick your tongue out and look for any coating on it. Expect it to be on the furthest back portion.
  • Take the gauze, and starting from the rear and working forward, wipe the surface of your tongue where the build up is heaviest several times.

Inspect the gauze.

Once you're done, smell and take a look at the gunk you've wiped off.

  • It likely has a yellow to brown color. Any coloration implies you'll discover breath problems.
  • When you smell it, it probably isn't all that pleasant.

    [If you're having trouble getting a whiff, you can amplify the odor by using the baggie trick described above.]

  • Whatever the results (good or bad), that's pretty much how your breath smells to other people.

A tried and true way to tell if you have bad breath.

Get someone else's opinion.

Another way to check your breath is an obvious one. Just ask someone else what they think.

Actually, this makes a very good plan and is generally regarded as a reliable way to confirm a chronic breath problem. That's because, as we described above, the human nose tends to ignore persistent odors, and even when doing testing like we describe above, it's still sometimes hard for us to smell ourselves.

Another good reason.

Beyond just not being able to detect our own malodor, there's another reason why getting an opinion from someone else can be important.

There's a condition termed pseudo-halitosis where the person suffering from it is under the impression that they have a breath problem but really don't. Or at least not to the extent they think they do.

So in cases such as these, asking someone else what they think can be very valuable in helping to lay to rest mistaken impressions and fears.

Who makes a good person to ask?

  • Obviously, if you have a significant other, they make a good candidate.
  • You might ask your dentist or hygienist at your next appointment. After all, evaluating the status of your oral health is their job.
  • If that's too personal for you, try asking a kid. Sometimes the least inhibited and most honest answers come from young children.
  • For best practices when using this method, see the "Considerations for subjects" list below in the "Organoleptic" section.

Continue reading this page ... about scientific testing for bad breath.

Or skip ahead ... to our next page that explains about the odors you smell and where they come from. After all, until you know about that, you won't be able to cure your problems.

How dental researchers measure halitosis.

( Related page: Bad breath classifications. )

Before a research study can evaluate the effectiveness of a cure, it must have a way to test for and quantify its subjects' oral odors. Here are some of the ways this can be done.

a) Organoleptic testing.

This is just a fancy way of saying that the tester uses their own nose to make the judgment. We mention it first because this is the oldest method of making an evaluation.

It's been used for numerous studies and it's easy enough to see why. Noses are readily available, they don't cost anything to operate, and to their credit, they can detect up to 10,000 different smells.

Considerations for the tester.

One obvious problem with organoleptic testing is that it's not totally objective (like machine testing is).

Additionally, when repeatedly exposed to a bad odor a person's sense of smell tends to acclimate to it and therefore loses much of its sensitivity. That means that breath that seems exceedingly objectionable at the beginning of testing may seem quite less so as the evaluation continues.

Another difficulty is that certain factors may influence the tester's judgment. For example, studies have shown that hunger, head position, degree of attentiveness and level of expectation may each influence the evaluation. Additionally, people who smoke, are pregnant, have chronic allergies or asthma tend not to make good judges.

Considerations for the subject.

The activities of the person being tested must be monitored too.

  • The consumption of garlic, onions or spicy foods should be stopped 48 hours prior to testing.
  • Scented cosmetics should not be used during the preceding 24 hour period.
  • The subject should avoid consuming foods, drinks or tobacco products for 12 hours before their assessment.
  • They should also refrain from using oral rinses, breath fresheners and omit usual oral hygiene practices 12 hours prior.

(Yaegaki 2000) [page references]

b) Gas chromatography.

A gas chromatograph is a scientific apparatus that can identify and precisely measure compounds in tested samples. The use of one of these machines for breath testing is considered to be the gold standard. That's because their results are highly objective, reproducible and reliable.

While being the most precise method, the use of gas chromatograpy isn't widely used in scientific studies. That's because these machines are relatively expensive, not portable, require special training to operate and require a significant amount of time to make each measurement. It's unlikely that your dentist has one.

c) Halimeters.

A halimeter is a specialized unit that's been specifically designed for breath testing. These machines (first introduced in 1991) measure for levels of sulfide gases. Sulfides, such as hydrogen sulfide and methyl mercaptan (collectively referred to as volatile sulfur compounds or "VSC's"), are known to be causative agents of halitosis.

Using our referral links for purchases supports this website at no additional cost to you. It's sincerely appreciated if you do.
Shop either ▶ Amazon related products below on this page, or else for any items on ▶ Amazon.com or ▶ Walmart.com.

As a drawback, Halimeters only tests for sulfides as a class and not as individual compounds. (A gas chromatograph provides a much more precise measurement.) Additionally, ethanol (alcohol) and essential oils, both of which are frequently found in mouthwash, can interfere with measurements.

As advantages, a Halimeter requires no special training to use, is portable, measurements can be made quickly and is comparatively inexpensive. Dentist who take a special interest in treating halitosis often have one in their office.

d) The BANA test.

Some of the types of bacteria that cause periodontal disease (gum disease) also produce smelly waste products that cause bad breath. The BANA test is a simple way a dentist can check for these bacteria, by way of testing a sample of their patient's saliva, dental plaque or a tongue swab.

The bacteria in question produce an enzyme that degrades the compound benzoyl-D, L-arginine-naphthylamide (abbreviated BANA). When this reaction occurs, it produces a color change in the BANA test's test strip.

When measuring low levels of sulfur compounds, this method provides better selectivity and sensitivity than a Halimeter.

Our next page explains what the odors you smell are and where they come from. Once you know that, you'll know how to cure your problems.



Topic Menu ▶  Bad Breath / Halitosis