Mouthwash’s Effect on a Breathalyzer


Today someone asked if mouthwash can affect the results of a breathalyzer and, if so, how. Since it’s not the first time that someone has asked this question, I thought that it would be a good idea to address the issue of whether mouthwash can affect a breathalyzer.

A breathalyzer is intended to analyze only the air which comes from deep within a suspected drunk driver’s lungs. The air that comes from the lungs is called alveolar air and any alcohol in alveolar air is related to the concentration of the alcohol in the blood. As the alveolar air passes from the lungs, through the mouth, and into the breathalyzer mouthpiece it can pick up residual alcohol that may be located in the mouth. This alcohol is called “mouth alcohol” and is not necessarily related to the consumption of alcohol or how intoxicated someone might be. Yet, mouth alcohol can cause a breathalyzer to produce an erroneously high blood alcohol reading.

So what causes mouth alcohol?

Mouth alcohol can be cause by many things. Cough drops containing menthol can get stuck in the teeth and cause an elevated BAC reading. Breathalyzers can detect alcohol that may be trapped in the small crevices of dental work or mouth piercings. Belching, vomiting, smoking, and chewing gum can cause vapors of alcohol located in the stomach to rise into the mouth. And yes, mouthwash can linger in the mouth after it is gargled and it, too, is mouth alcohol.

Although none of the above mentioned causes of mouth alcohol leads to intoxication, all of them can cause a false-positive BAC reading on a breathalyzer.

The answer is “yes.” Mouthwash, along with a number of other things, can cause a breathalyzer to produce an incorrect blood alcohol reading which, in turn, can cause a person to be falsely arrested for DUI.

This entry was posted in Chemical Tests, DUI Laws, Field Evidence and tagged , , , . Bookmark the permalink.

56 Responses to Mouthwash’s Effect on a Breathalyzer

  1. Rich Ronning says:

    My wife blew a .054 from mouthwash on an interlock system and they revoked her license and made her start over from day one after being on it for 18 months of the 3 years she was given. WTF?? Can we fight this in the state of MN.?

    • PC Plod says:

      Erm no… they test with a evidential test at the station mouth wash effects would not be so long lasting she was drunk and deserves prison

      • Dave says:

        Youre an idiot. You dont know a damn thing about her. You also dont know a damn thing about the law or alcohol because the legal limit is 0.08 and she blew a 0.05. Secondly- he said “on the interlock” not “at the station” so you clearly cant read either.

        • Katie says:

          This is BULLSHIT I feel your pain literally just brushed my teeth and blew into my intoxalock brethaltzer blew a .175 than a .44 WTF

        • Ashton says:

          With an interlock the reading has to be 0 ?

        • Lori B says:

          Amen to that. So judgmental!

        • Roxann Patrice Gregg says:

          A friend of mine was given a breathalyzer test at work first he blew an 84 then 15 minutes later he blew a 94 he smokes cigars and with this covid-19 pandemic and having to wear a face mask he gargles every morning before leaving the home and placing the mask over his face. He was terminated for being intoxicated. Can he fight this

        • Spencer says:

          Your wife lied to you dude get over it.
          She likes to drink.

    • David Linge says:

      i woke up this morning and couldn’t find my lighter. Got up and brushed my teeth and took 2 mouthfulls of Listerine. Went to the store to buy a lighter maybe 5 minutes after i used the mouthwash. Got pulled over and i blew a fail. Even the cop said mouthwash can throw a roadside screening device off. He charged me anyway. Good thing I have a good lawyer. I appealed and most likely the charges will be thrown out. I passed all the heel to toe tests, did the follow the pen with my eyes, and did the 12 step walk and passed all tests. No more mouthwash for me if I’m going to drive.

  2. Lawrence Taylor ESQ says:

    Rich,
    I’m sorry for your troubles.
    We can definitely fight for your rights and work to getting this decision reversed.
    The first step is to call my office for a free consultation to review your case. Please call to schedule an appointment: 877-777-3449.
    I’m here for you Rich.

  3. Benjamin says:

    I was test positive for alcohol by means of a breatherlizer.Half an hour pryer to the test i flush my mouth with corsodyl,is it possible

  4. Felisha Mitchell says:

    My seventeen year old son was pulled over and charged with minor consumption. He had just rinsed his mouth out with Listerine and had finished breath mints before he was pulled over. He blew a 0.037 is what the officer told my mother when he realeased my son to her but the officer put in the report that he blew 0.05. My truck that he was driving was impounded It cost me $180 to get it out of impound. We havent been to court yet but I already feel like we are being railroaded. We could use some help.

  5. Emily fresquez says:

    how will it get dropped? i have court tomorow and im 19
    with the same proplem

  6. todd says:

    Got pulled over 2 weeks ago , cop said I was weaving blew .10 told them both I had mouthwash ed due to cigar smoking, not to mention having had a stroke 3 years ago and no balance so I failed the field test

  7. Rachel says:

    I did have 2 glasses of wine hours before driving but went through a check point i was honest about the two hours ago i didn’t think i had done anything wrong i later rewent through all steps before i got in my truck i washed my mouth with mouth wash they are saying.10 im so shocked i had lunch after my wine i saw places in the city i was fine could this be true?

  8. Rosa says:

    Rachel. I also had drank 2 glasses of wine I told the officer and I rinsed my mouth with listening and chewed gum and I blew 0.09 and trust me.officer tested my abc’so and counted backwards and the pen test leg test and he still arrested me he said my eyes said I was intoxicated.I am so scared right now

  9. Rosa says:

    Oops spell check listerine

  10. Beatles4Ever says:

    This thread has helped me greatly tonight so thank u everybody. But I have a question that someone can hopefully honestly help me out very soon because I have work in a couple hours. The question I have is how much alcohol will technically be in your system if you use listerine (or any other mouthwash that contains alcohol) before work? I usually get non-alcohol mouthwash but I ran out of that so now I’m back to listerine haha. This is a new thing to me that is kinda worrying me. I’m sorta young like I’m nder 21 so I can’t legally drink alcohol at all. Where I live we have a zero tolerance for underage people driving with any bit of alcohol in their body so if I get breathalyzed I’m gonna get some bad shit coming my way. I just got a delivery driving job so I feel like this is kind of important in case I get pulled over cuz I’ll lose my job and get into stupid court issues. Sorry for rambling haha but how much alcohol will be in my system in like 3 hours after I use the listerine? I tried to google it but ended up getting a lot of different answers

    • joseph hickman says:

      call in sick, better than from jail. u can always get another job with a clean record,and car insurance!!!

  11. Beatles4Ever says:

    please respond as soon as anyone is able to. Sorry if I’m just being paranoid for no reason. I’m just a pretty new driver and I’m trying to learn as much as I possibly can

  12. Peggy says:

    Had someone say he used scope. When blood work was done for alcohol it showed .03. Is this possible?

  13. Jay says:

    I used mouthwash and blew a false positive on my breathelyzer at 10 and then again at 10:10 and again at 10:50 how is this possible and how should I argume my case against this bullshit

  14. Goodropi says:

    I. Got failed a breath test at probation for a little over an hour the other day. I had used the green listerine and now my po is making me go to jail for 20 days. I have not had a bad UA or failed a breath test in 4 months. I don’t know what to do because the 20 days should have been waived and now I am losing my job and everything.

  15. Jan says:

    If you used mouthwash and had no drinks, reuse the breath test and make them take you to the hospital for a blood test.

  16. Dean says:

    I use prescription mouthwash 12% alcohol with my interlock and sometimes it takes up to 30 minutes. I get warns, no fails. I am under doctors care for infection. So, not to much probation can do about it.

  17. Christopher says:

    How long does it take for me to pass the breathylizer after using Listerine?

  18. mike says:

    i blew a .27 after leaving my house 10 mins later a .07 and then a .00000. now im being punished cuz i ran out house in a hurry after using Listerine. anyway to beat this???

  19. mike says:

    10-15 min between each bac.

    • Rachelly Castles says:

      That is crazy because I blew on my test and was a little over the legal limit after a few hours after drinks and eating. I was good, went and washed my mouth out with green minty listerine. Didn’t think anything about it and some broad hit me while I had a protected left at the light. It was awful because I had a friend in my vehicle beforehand and she left her bottles underneath the passenger seat. So, they didn’t give a crap about what I had to say. The whole thing was horrible. The girl that hit me had a boyfriend who was trying to fake injury and had wrapped a blanket around himself and threw himself on the floor and hollered “help! help!” It was a horrible night.

  20. Al says:

    Just used mouthwas with alchohol in it and blew a violation on my mass interlock system so I came back inside ate breakfast and drink a bottle of water and rinse my mouth out with water several times and I am afraid to go back out there and blow again , how long do you think i should wait?

  21. Charles says:

    I brushed my teeth this morning and wash my mouth out with Listerine And could not stop my car And was taking holes menthol cough drops for my sloth road I don’t know which one affected the Breathalyzer

  22. Charles says:

    Listerine and halls cough drops dont use dont know why witch one Interfered with my interlock does anyone know

  23. Ashley Hill says:

    Could an alcohol free mouth wash give a false positive result?

  24. KENNETH RYAN says:

    Well I just got fired from my job blowing a .012 from mouth wash so it can happen be careful what you do society don’t play love hate and it don’t matter if you lie or not your screwed thank all you other idiot’s.

  25. Bobby Pastor says:

    I think that what must be considered is that the police (besides an unlucky random breath test) will only pull u over and test u only if u have committed some traffic violation.

  26. 1st of all in court one should always request the last calibrations of the breathalyzer unit. 2nd one should always request a blood or urine test over a breathalyzer test anyways.3rd avoid thinks like mouth wash & mints. Wine is I’d think harder to avoid thrn beer or hard liquor Aged grapes that become alcohol seem to have a longer lasting affect in the mouth. One that drinks it does not notice this as much but the alcoholic smell lingers to the point one not drinking could almost get drunk off of your breaths Vapors. Wine does not seem like a good choice for one to drive after drinking based on it’s nature I’m sure it’s trapped in ever area of your teeth just as it can stain your teeth too. If your a wine drinker refuse the breathalyzer & request blood or urine test instead.You are not required as far as I know to except a breathalyzer but you are required in most states to give blood or urine sample for testing.

  27. Tim says:

    I got stopped and the officer said he could smell alcohol I told him that I had dentures and had them sitting in Listerine and a efferdent tablet I blew into a breathalyzer and it came back 0.04 can I fight it

  28. Martin Enright says:

    Why is it in the UK that they can prosecute you even if you asked the police to take a blood sample.

  29. Ovus Medical says:

    Breathalyzers can detect alcohol within 15 minutes of your first drink. So how long can a breathalyzer test detect alcohol? As long as the alcohol is in your system, nothing can make you appear sober. Sleeping it off, taking a cold shower, or drinking coffee won’t make you appear to be any less drunk or any soberer. Only time can lower your BAC.

  30. David Linge says:

    On Friday May 5th I woke up at 8:57. Being a smoker, the first thing I wanted was a cigarette, but couldn’t find my lighter. I only have 2 chewing teeth left and my last dentist appointment I was told to use mouthwash twice a day. I went to the restroom and brushed my few teeth and gargled with store brand mouthwash and went out to my car to drive to the nearest store (90 seconds drive away to buy a lighter). I had the mouthwash in my mouth and spat it on the ground outside my car. I was gone for maybe 4 minutes maximum. I got home and parked when a cop came speeding up behind me with lights and sirens. I drive a 1978 Oldsmobile with 51,000 original miles on it and it just passed inspection. The first thing the cop said to me was “How much listerine you been drinking today?”. I thought WTF, does this cop have a camera in my restroom? I told him as a matter of fact, I did just use mouthwash about 5 minutes ago. He told me to blow into the roadside screening device and I had no doubts I would pass as I had not consumed any alcohol. I blew a fail. I asked the cop to take me to the police station to get a blood test, but he started screaming so loud that I would get more criminal charges and he would cuff me in front of my house and neighbors and embarrass me. I’m under a doctor’s care for anxiety, and the cop basically shouted me down so badly, I was terrified. I have numerous witnesses who have known me for over 40 years and they want to testify that I wont drive even after a sip of beer. I can’t afford a lawyer. I believe this is extremely unfair as I did ask for a blood test. I filed an appeal. A legal aid lawyer I phoned less than 1 hour after being charged, and he said to immediately request the dashcam footage. I contacted the cop less than an hour after I got pulled over and asked for a copy of the dashcam video. His response? “I’m real sorry, but it got lost”. Very unfair, especially when you cant afford a lawyer. I knew mouthwash had alcohol in it, but I dont drink the stuff, and was unaware it could throw a breathalyzer off. All mouthwash containing alcohol should have warnings on the bottle to say not to use before driving. I’m very upset about the whole thing.

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  32. Gary Lee says:

    I used Scope prior to arriving to work then 90 minutes later after a breakfast smoothie, to avoid bad breath. 12 hours prior at 10:30 pm had two glasses of wine. At my clinic I was told I looked drunk, I wasn’t but still lost my job because an independent annalist. I explained fully my activities. I work in medicine and know my responsibility to my patients very well.

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