Proven Ways to Pass a Mouth Swab (Saliva) Drug Test

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

Last updated on Sep 26, 2023

A mouth swab drug test can only detect the use of marijuana in the last 3 days. So if you last smoked a week ago, you are safe.

After smoking marijuana, some of the Delta-9 THC or Delta-8 THC sticks all over the surface of your mouth. All you need to wash out that THC to pass the mouth swab drug test.

Here are the remedies that helped over 50,000 people to sidestep detection.

You’ll need

  • 3% Hydrogen peroxide mixed with water (70% peroxide 30% water)
  • OR Listerine
  • OR Plain water


Hydrogen Peroxide



The hydrogen peroxide will clear the traces of the drug from your saliva. It is handy to carry the hydrogen peroxide to the drug test location and use it as near the test as possible.

You can use any other liquid from the list instead of peroxide.

Important tips for success

If you have a couple of days before your drug test, follow these recommendations to increase your chances of passing.

Since your employer might decide to conduct a mouth swab drug test randomly, it is ideal that you keep a small bottle of detox mouthwash at hand.

They are highly convenient to carry around, easy to use, and no one will suspect anything fishy if you’re swishing some mouthwash during break time.

How does this method work

When you consume weed, THC gets into the blood through the lungs or the stomach walls(if you use edibles).

After that, it is metabolized and excreted. But it never gets into the saliva.

The only THC in your mouth is THC that sticks to your mouth during smoking.

So all that you need to do is to wash it out of your mouth with water or any other liquid.

Why should you use detox mouthwash, and how does it work

Combined with oral fluids, the rapidly-acting ingredients in a detox mouthwash efficiently cleanse your mouth of unwanted toxins.

And the best bit is that adulteration tests cannot identify them, so there’s no chance of being caught cheating.

But there are a few things to remember about detox mouthwashes:

How far back will a mouth swab drug test go?

Traces of weed are detectable in saliva for up to 3 days after the last toke. Other drugs are detectable for up to 10 days.

Here’s the chart, showing the detection times of different drugs.

How to pass a mouth swab drug test: detection times chart

Why doesn’t THC stay in saliva for very long?

THC metabolites are fat-soluble and are stored in body fat tissues. Since there are no fat reserves inside the mouth, there’s nothing to keep THC inside your mouth or saliva for a very long time.

The only thing that makes THC detectable in swab tests is the smoke that coats the entire inner surface of the mouth, from where a sample of THC can be collected by gently scrubbing the inside of the cheek.

Can CBD Make You Fail This Test?

No. Remember that CBD is not a psychoactive substance; hence it will not be tested in tests designed to detect marijuana use.

Since THC is the only cannabinoid checked for in drug tests, CBD alone cannot be identified in a common mouth swab drug test.

So good news: you can use pure CBD without the fear of failing a saliva drug test.

BUT, the cannabis strains from which CBD is extracted usually contain low concentrations of THC.

Even though smoking these weeds won’t make you fail your drug test, there is a slight risk when using concentrated CBD oil.

Since concentrated oil makes THC levels rise, consuming a large quantity can theoretically cause a positive THC result.

To avoid this risk, use a detox mouthwash after consuming such products.

What is a mouth swab drug test, and why is it done

A mouth swab drug test, also known as the oral fluids test or saliva drug test, is a screening test used to assess substance use. A typical cotton swab is brushed on the inside of your cheek to collect a saliva sample, and you’re good to go.

These tests are generally used as a replacement for urine drug tests, and this is because they’re a) straightforward and quick to administer and b) collected right in front of the person conducting the test, so there’s a pretty slim chance of foul play.

Mouth swab drug tests are commonly used during pre-employment screening, period or random testing, and also after something suspicious might have happened at the workplace, i.e., related to drug use.

Certain police forces also use this test for roadside drug testing if they think a person could be driving under the influence.

What do mouth swab drug tests look for

Unlike urine tests, which look for the active metabolite THC-COOH, oral swab tests detect THC itself. This makes this test more reliable and efficient since THC remains in saliva for at least 24 hours before being metabolized by the body.

Here are the details of the detectable drugs, their cutoff levels, and their approximate detection times.

Drug Cut-Off Level (ng/mL) Detection Time (hours)
Amphetamine (AMP) 50 72
Cocaine (COC) 20 72
Marijuana (THC) 12 24
Methamphetamine (mAMP) 50 72
Opiates (OPI) 40 36
Benzodiazepines (BZO) 10 240
Barbiturates (BAR) 50 24

Generally, the detection window for oral fluids is 5-48 hours, but this window can be longer for regular and long-time users.

How long does a mouth swab drug test go back?

Drugs mostly become detectable in oral fluids within around 30 minutes of consumption, which is way faster than other tests.

This shorter time frame makes the mouth swab tests particularly effective for screening after accidents or in suspicious situations.

However, these are just generalizations. How long a swab drug test can detect a substance typically depends on the:

Limitations in Oral Drug Testing

The most significant disadvantage of a swab drug test is when these drugs and their metabolites remain present in saliva.

As you may have noticed from the table above, the detection windows for drugs are far shorter than other methods – only a few hours to days, unlike weeks and months for urine tests.

This means that a person can stop using for a few days, test clean, and start using again!

Another limitation of swab drug tests is that certain medications can potentially interfere with and lead to inconclusive results. For instance, cough medicines containing codeine could impact the outcome of an opiate test.

And thirdly, unlike urine and blood tests that detect a large variety of drugs, some drugs cannot be identified in the saliva at all, which leads to limited testing prospects.

Which Employers Use Mouth Swab Drug Tests

To answer the questions of those looking for a job, any employer wanting to make sure a prospective candidate hasn’t been using drugs or isn’t using drugs while on the job can conduct a swab drug test.

This can mean educational institutions, jobs that require working with heavy machinery, and jobs that involve driving. Most federal positions require drug testing, and industries such as transportation, aviation, and defense are required to test applicants and employees for substance use.

When do employers use mouth swab drug test

There are many common occasions where employers would want to conduct mouth swab drug tests. These include the following:

Here are the results of the survey among the drug tested persons:

Question: I found the oral fluid swab test procedure more or less uncomfortable than the urine test


Mouth swab drug test survey

Do I have to take a mouth swab drug test?

The good news is that your employer cannot force you, or a potential job candidate, to take a mouth swab drug test.

But the bad news is that there can be negative consequences if you refuse to take the test.

Refusing to take a pre-employment oral drug test means that the employer can withdraw the job offer. Refusing to take a drug test while on the job could cause your company to fire or suspend you or refuse a possible promotion.

To avoid any confusion, it’s always a good idea to enquire about your company’s drug testing policy. You can ask someone from human resources for more information regarding these matters.

How a mouth swab test is conducted

The mouth swab drug test is the least invasive type of drug test; no poking needles or peeing in a cup.

Plus, these tests don’t require much preparation at all! You’ll only be asked not to eat or drink anything for at least 10 minutes before the test.

A mouth swab drug test is done using these basic steps:

  1. A collection stick – a typical cotton swab with an absorbent pad or sponge on one end – is used to scrub the inside of the cheek gently.
  2. The sample is enclosed in an air-tight sterilized bottle or container and sent for analysis, either on-site or in a lab.

What is an inconclusive saliva test?

An inconclusive test means that the results could not conclusively determine that a person was using drugs. Many factors could cause this, such as:

If you believe your test results are inaccurate, you can take another test or have the test results reviewed.

What is the range of risk for failing a mouth swab drug test?

Technically speaking, you’re at risk of failing a mouth swab drug test if the concentration of THC in your saliva is more than the lower range of the cut-off value of the test. This is also called the ‘confirmation cut-off.’

Different tests and different states have different legal cut-offs for marijuana intoxication. Sparing you the details, you’re most probably out of the risk range if you stop using marijuana for at least 24-48 hours before your test; a week-long break would be even better.

Bottom line: the range of risk for failing a mouth swab drug test is fairly short. Basically, these tests are used to see if you’re high at that given moment.

Frequently Asked Questions (FAQs)

Q. How to produce saliva fast enough for the mouth swab device?

Certain drug-testing devices are flavored to stimulate the flow of saliva without hampering test results. Similarly, certain kits come with a minty tip for people who cannot produce enough saliva quickly.

Q. How far back does an oral fluid drug test go?

A mouth swab can assess whether someone has used drugs in a 3-24 hours window; hence these tests have the shortest detection window, which is extremely suitable for suspicion testing.

Q. Are oral drug tests accurate?

Oral fluid tests are highly reliable point-of-care tests (POCT), providing results in a matter of minutes.

Q. What are the benefits of mouth swab drug testing over urine testing?

Q. What does it mean when a mouth swab drug test turns blue?

The sample adequacy window of the saliva drug test turns blue when the sample quantity is adequate for testing. This reduces the need to do any guesswork while collecting oral fluid specimens and reduces the need to repeat collections.

Q. How do you know that you failed the mouth swab test?

Swab tests are straightforward to interpret. Negative and positive test results are displayed as colored lines on the drug panel of the test kit.

Q. What should you do after you failed to pass a mouth swab drug test?

There is nothing much that you can do after a confirmatory test comes back positive.

However, don’t just give in, especially if there is a lot at stake.

You might consider fighting back- but in a calm way.

We’ve heard cases of people who tested positive for drugs they had never used before.

This could be you. Act very surprised and claim that something must have gone horribly wrong.

Let them believe that there must have been a mistake somewhere and insist on taking a urine test instead.

If you are lucky to redo a urine test, then do everything possible to piss clean.

The convenient and guaranteed solution to pass mouth swab drug test
Stinger Detox Mouthwash

  • Removes alcohol, nicotine, marijuana (THC), cocaine (COC), amphetamines, methamphetamines, opiates, etc.
  • Works in 2 minutes
  • The effects last for 30 minutes.
  • Alcohol-free
  • FDA registered & USA made
  • Legal
  • Not detectable
  • Small and discreet

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.