Does Mouthwash Affect the Breathalyzer Test?

As we all know, a lot of mouthwashes have alcohol in them.  Mouthwash companies say they use alcohol to freshen breath and kill germs, but it is hard to find if that is the real reason alcohol is added.  I could not find any study indicating that alcohol is really necessary to solve those problems.

After looking into alcoholic mouthwashes, I began to wonder if there is any medical information on alcoholic mouthwashes and the effect of breathalyzer tests.  It appears that a limited number of medical studies have been done on this subject.

Alcoholic mouthwashes does not affect breathalyzers

An older study, one done in 1994 by the University of Alabama School of Medicine, indicates that the use of mouthwash immediately prior to breath testing, as might occur in the car or workplace in a mistaken attempt to hide the smell of alcohol or other substances, may significantly increase the measured breath alcohol values. According to the National Highway Traffic Safety Administration (NHTSA), there is no evidence that such substances affect the standard breath analysis tests when conducted properly or that other challenges to the accuracy of alcohol detection equipment are valid.

An assignment, at the Department of Chemistry at the University of North Texas, was for students to test a breathalyzer after the use of an alcoholic mouthwash.  Their lab assignment states that one potential problem with the Breathalyzer is that ethanol vapor can also come from the mouth.  If a person has recently rinsed with mouthwash, the Breathalyzer test will be positive because mouthwash has an alcohol concentration ranging from 6 to 27%.  The residual alcohol stays in the mouth and can register a false positive on the Breathalyzer test.

Fortunately, the effects of rinsing with mouthwash diminish after a short time .

Easy to use breathalyzers

The Alcohawk Slim Digital Breathalyzer, which measures blood alcohol concentration within a range of 0.000 - 0.400%.


  The BreathKey Keychain Breath Alcohol Tester, which does not specify the blood alcohol concentration it can measure.


The BACtrack S80 Pro Breathalizer, which measures 0.000 - 0.400% blood alcohol concentration.


I could not find any medical studies indicating how long this measurable effect may last in your mouth, but waiting fifteen minutes was necessary to ensure there was no residual mouth alcohol, before taking a breathalyzer test according to the Forensic Sciences Program at the University of California.

I did not look up all the laws in the states, so I wasn't even taking laws into consideration.  I was only looking this up as medical information, even though .08 blood alcohol level is the legal limit in most states.


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