Step-by-step Guide on How to Pass a Saliva Drug Test With Listerine

Daniel Miller
Daniel Miller, Ph.D, Drug Testing Specialist

Last updated on Apr 8, 2024

You must have heard that Listerine helps in passing the saliva (mouth swab) drug test. You must also be wondering, ‘‘Man, will this really work?”

I have to admit that this method seems a little bit farfetched and more of another internet rumor. Take it easy, though. It’s true that Listerine works most of the time.

But studies show that water also works.

This article will show you how to pass a saliva drug test with Listerine or Listerine strips.

I’ll also explain how and why it works and how you could use water instead.

listerine for drug test

Can you pass a saliva drug test with Listerine?

Yes. Most people continue to pass swab tests using Listerine strips today, and many scientific studies prove that it really works.

They also brush the mouth with Listerine or even swallow it,

Perhaps the saving grace in this method is that the components of Listerine do not show on the tests, at least for now.

Thus, it’s not easy for the lab guys to detect that you are trying to cheat the test.

The internet community has several methods of using the Listerine method of passing saliva tests.

Here is the most common regimen;

What you’ll need

How to Pass a Saliva Drug Test with Listerine: Instructions

Step 1: Abstain from Cannabis and other drugs for at least 48 hours

Some saliva tests today will detect cannabis 48 hours since your last hit.

That being said, it’s a brilliant idea to keep off the weed for at least 2 days or even 3 if you seriously want to pass that test.

Of course, you might not have 48 hours if you’ve just been informed of a possible saliva test on the same day.

That might be a tough situation to be in. But we’ve heard of guys who beat the test at 9 am even after stoning late into the night the previous day.

If you are in this situation, you’ll want to take the next steps in this method even more faithfully.

Step 2: Eat and Drink to keep your mouth moist

Beating a mouth swab test is all about getting rid of the saturated saliva in the mouth.

To do this, you’ll need to keep the water content in your mouth moving. One sure way of doing this is to eat and drink.

You don’t really need to change anything in your morning routine, especially if you have 48 hours or more to the test.

However, if you don’t want to take any chances, you might want to consider foods that make you salivate more and those with high water content.

These include apples, carrots, cucumbers, celery, pasta, and cheese.

Foods with spices such as cayenne pepper, cardamom, cayenne, and ginger also play a huge role.

It’s also a good idea to avoid foods that aggravate dry mouth, including soda, dry crackers, salty nuts, popcorns, and sugary desserts.

Step 3: Brush your teeth, tongue, and gum.

When I say brush, I mean to do it like crazy. The essence here is to remove as much THC as possible.

Reliable sources advocate brushing 3-4 times each day (as usual).

However, you might want to brush for a few more minutes than the 2 minutes that dentists recommend.

When brushing, you want to ensure that you give equal priority to the teeth, tongue, top, bottom, and sides of the mouth.

You could also use Listerine, although you’ll need it the most on the ‘D-day.’

Using dental floss might also increase your odds of passing the test since it reaches where your brush doesn’t and, therefore, aids in getting rid of more THC molecules.

Step 4: Day of the Test

On the day of the test, you need to descend on the remaining molecules like never before.

Here, you’ll want to extend the brushing time to up to 15 or 20 minutes.

You’ll also need to swish Listerine at least 4 times and as many times as possible before heading out.

Importantly, let the mouthwash absorb for 45 seconds to 1 minute before spitting it down the plughole.

Yes, Listerine stings like hell, especially if allowed to sit in the mouth for long.

But that’s nothing compared to what a FAIL in the drug test might make you feel.

Step 5: Heading to the venue

One hour to the test, pack a small amount of Listerine and a bottle of water. On the way, rub 2 Listerine strips into each cheek and let them dissolve.

Take another pair of strips and dissolve them under your tongue.

The essence of this is to absorb any molecules that may have eluded all the brushing and swishing so far.

If you don’t have Listerine strips, you could buy a pack at the local candy or drug store near you. Each pack goes for around 2 bucks.

Step 6: 30 minutes to a collection

30 minutes before the test, swish Listerine for the last time and rinse with water.

Take 2 more strips and rub the cheeks for the last time before facing the lab technician.

How Swab Drug Tests Detect Marijuana

Saliva drug tests are becoming more common not only in post-accident testing but on the job testing too. The reason for this is that they are supposedly more accurate than urinalysis.

You see, unlike a urine drug test, a swab test shows whether you’ve had a hit in the recent past or not.

These tests will detect marijuana for up to 72 hours since you last had your last toke.

Therefore, it accurately informs your employer, potential employer, or whoever is taking the test whether you have used the drugs recently or not.

This can be either good news or bad news, depending on your status at that specific test time.

On the one hand, it means that unlike a urine drug test that can detect THC for up to 30 days, a swab test means that you won’t be convicted of a ‘sin’ that you committed almost a month or 2 ago.

On the other hand, remember that THC is detectable in your mouth immediately after stoning and will hover around for up to 24 hours.

This means that it’s quite difficult to cheat this test unless something is done, especially if you’ve held a hit within the last 24 hours.

The other thing that makes a saliva test bad news for you is that it can be administered anywhere (by the roadside or at the job site) at any time with or without warning.

What does a Swab Drug Test Look for?

If you’ve read our other articles on urinalysis, you must know that urine tests check for THC-COOH, also known as 11-COOH-THC.

This is a metabolite formed after THC has been metabolized, and it’s detectable in urine and feces.

A saliva drug test is quite different, though.

This test looks for activated THC (delta-9 THC). This is the psychoactive compound that gives you the HIGH effect when you inhale or eat marijuana.

A puff of marijuana harbors millions of activated THC molecules.

A good portion of these molecules remains in your salivary albumin concentration, mostly in your oral cavity, and this is what gets you in trouble.

How long is THC detectable in the saliva?

As with any other test, your chances of fooling a swab drug test highly depends on how long the THC in your mouth remains within the detectable levels.

A study published in the Journal of Analytical Toxicology aimed at investigating how long THC stays in the mouth in the controlled administration of smoked marijuana.

In this study, 6 subjects were required to smoke cannabis cigarettes containing 1.75% THC in the first week and another one containing 3.55% THC in the following week.

In each experiment, saliva specimens were analyzed for the concentration of THC by GC-MS (Gas Chromatography-Mass Spectrometry).

12 minutes after initiation of smoking, one specimen recorded a THC concentration of 5800 ng/ml.

At around the 20th minute, this concentration had subsided to 81 ng/ml. 12 hours after the test, another test showed that the concentration of THC in the saliva specimens had fallen to below 1 ng/ml.

The researchers noted that this pattern of initial high THC concentration levels right after smoking, followed by a decline, was recorded in all the subjects.

They also stated that the decline in the concentration levels with time suggests that there might be a direct absorption of THC into the bloodstream directly from the mouth.

As we can deduce from the study above, THC stays in your mouth for up to 12 hours after a puff.

The good news, however, is that the concentration declines with time.

Most labs use a cut-off level of 10-25 ng/ml, depending on the test type.

While the study above shows that THC will be way below the detectable levels 12 hours after the last puff, it’s worth noting that there are tests that can detect cannabis 48 hours after an encounter.

Besides, remember that the THC molecules may linger around for a little longer depending on a few factors, including;

How Listerine works in Saliva Drug test

One common question that most of our readers throw our way is, ‘‘how does Listerine work to help beat a saliva test?”

Well, the jury is yet to come up with a concrete explanation of what really happens here.

However, there are a few suggestions that have been put forward.

The major belief is that it cleans the THC molecules just as it eliminates bacteria in the mouth.

Others believe that it uses its bacteria-killing power to destroy THC, thereby making it undetectable.

Still, some believe that the active ingredients in Listerine (menthol, thymol, methyl salicylate, and eucalyptol) interfere with the test’s performance making them record a false negative.

Listerine vs. Water – what works better? Scientific Research Results

Listerine does help in passing a swab drug test. However, studies show that water works similarly and perhaps even better.

A 2014 study aimed at assessing the effect of different mouthwashes and water on cannabis oral fluid concentrations.

This study involved 11 chronic cannabis smokers and took 4 days.

On the first, second, and third days, the subjects smoked their daily doses.

Oral fluids were taken 30 minutes before smoking and at 15 minutes, 30 minutes, 1 hour, 3 hours, 6 hours, 12 hours, and 24 hours after smoking.

The participants used water, Kleaner, and whole milk, and specimens were analyzed for THC concentrations.

Significantly lower THC concentrations in the oral fluids specimens were observed after a water rinse than with Kleaner and milk.

It was also found out that 15 minutes post-smoking, the THC concentration level was 3 folds higher than the 25 ng/ml cut-off used by Spanish police regardless of the type of mouthwash used.


There’s no doubt that Listerine can help you pass a saliva drug test.

But what’s more amazing is that you can use water and still pass.

This means that you don’t have to spend a buck to pass a saliva test if you don’t have Listerine at home.

The information on this website about detox products and synthetic urines is for educational purposes only. We do not endorse or condone their illegal use. Always consider the laws in your area and the potential legal consequences. Consult with a healthcare professional before using any products. Your responsibility and well-being are paramount.