Can mouthwash make you flunk a breathalyzer test?

[UncleFred]

Here in Boston we're all a doo-dah about a state senator who got put on a house-arrest no-drinking probation after a hit-n-run incident. Not one week into his house arrest he flunked one of several daily breathalyzer tests.

He claimed he hadn't been drinking and that it was a false positive caused by his toothpaste. The judge didn't buy it and now the senator's in the slammer.

But wait - doesn't mouthwash have a high alcohol content? Something like 15%? You don't drink it, but it lingers in your mouth and on your breath.

Could using mouthwash right before taking the test result in a failure?

Or maybe its the 'wrong' type of alcohol?

[beowulff]

Didn't you say toothpaste?
That doesn't have any significant alcohol in it, AFAIK.

Mouthwash - maybe.

[UncleFred]

Originally Posted by beowulff

Didn't you say toothpaste?
That doesn't have any significant alcohol in it, AFAIK.

Mouthwash - maybe.

Like I said...the judge didn't buy it.

[pravnik]

The breathalyzer is designed to measure deep lung alcohol. Mouth alcohol can cause a false positive if the alcohol is ingested (or swished around) immediately before taking the sample, as can stomach alcohol if the subject burps or regurgitates. To avoid false positives due to mouth or stomach alcohol the subject is observed for a minimum of 15 minutes prior to taking the sample. Some breathalyzers also have a feature that measures a very sharp dropoff in alcohol in the first part of the breath and the last part - if the subject is blowing much higher during the first part of the blow the last part, there could be mouth alcohol contamination and the instrument will read the test as invalid.

[Shagnasty]

The academic answer is that it can under the right circumstances. Mouthwash like Listerine is 54 proof alcohol for example. You can swish some in your mouth and take a breathalyzer immediately and flunk it. You wouldn't flunk a blood test however from that unless you actually drank a lot of it (which some people do if they are desperate).

The answer to the larger question is that he was lying or the equipment was faulty (less likely for the latter). I am a recovering alcoholic with a lab grade breathalyzer and have done these experiments on myself. You can 'trick' them into a high reading pretty easily with alcohol containing products but that will go away in a few minutes if you wash your mouth with water. Toothpaste won't cause a failure reading at all.

[BigT]

OP reminded me of a reverse version of this urban myth.

[Fear Itself]

Originally Posted by beowulff

Didn't you say toothpaste?
That doesn't have any significant alcohol in it, AFAIK.

Most toothpaste has a significant amount of sorbitol (up to 30%). Sorbitol is a sugar alcohol, but i don't know how it would affect a breathalyzer.

[muldoonthief]

Originally Posted by Fear Itself

Most toothpaste has a significant amount of sorbitol (up to 30%). Sorbitol is a sugar alcohol, but i don't know how it would affect a breathalyzer.

The manufacturer of the breathalyzer that nailed Gallucci claimed it wouldn't affect it at all. And at his hearing, Gallucci dropped the toothpaste defense, and instead, brought in an outside expert who testified, using a testing method of his own that has not been approved by anyone, that Gallucci hadn't had a drink in the past 4 weeks. This worked flawlessly, in that a dangerous drunken driver who couldn't even remain sober for a week after his suspended sentence has been placed in jail.

[TurboNuke]

I was just on a jury for a DWI case. We heard a lot of testimony about breathalyzers. The breathalyzer in NY is a fairly foolproof device. Can "mouth alcohol" affect the test? Yes. But the tester also knows when this happens and it will invalidate the test.

IMO, there is really no way to fool or cause the breathalyzer to read spuriously.

[UncleFred]

Originally Posted by muldoonthief

The manufacturer of the breathalyzer that nailed Gallucci claimed it wouldn't affect it at all. And at his hearing, Gallucci dropped the toothpaste defense, and instead, brought in an outside expert who testified, using a testing method of his own that has not been approved by anyone, that Gallucci hadn't had a drink in the past 4 weeks. This worked flawlessly, in that a dangerous drunken driver who couldn't even remain sober for a week after his suspended sentence has been placed in jail.

A friend just informed me that the senator failed the breathalyzer not once but three times on that one day. That probably helped kill the toothpaste defense.

[Fear Itself]

Originally Posted by TurboNuke

Can "mouth alcohol" affect the test? Yes. But the tester also knows when this happens and it will invalidate the test.

In Gallucio's case, he was being tested remotely by a device in his home. If there was an operator, he would have no knowledge of the conditions surrounding the test.

[muldoonthief]

Originally Posted by Fear Itself

In Gallucio's case, he was being tested remotely by a device in his home. If there was an operator, he would have no knowledge of the conditions surrounding the test.

No - it was the day the device was being installed. The installer had him do a test right then and there, which he failed. He did say something like he thought it would be a few weeks before the device was ready - which I interpret as "I wouldn't have breakfasted on bourbon if I knew you were coming today."

[RickJay]

My wife once failed a breathalyzer test because she'd used a Listerine mouthwash strip immediately before being tested. She got out of being arrested by asking the police officer to try one and test himself - which he did, and failed the test himself. (They were perceptive enough to notice she wasn't acting drunk and so were willing to try out her explanation.) Absolutely true story, happened in 2001 in Mississauga, Ontario.

So yes, it can happen. I suspect, however, that the use of mouthwash must be immediately before the test.

[billfish678]

Originally Posted by RickJay

My wife once failed a breathalyzer test because she'd used a Listerine mouthwash strip immediately before being tested. She got out of being arrested by asking the police officer to try one and test himself - which he did, and failed the test himself. (They were perceptive enough to notice she wasn't acting drunk and so were willing to try out her explanation.) Absolutely true story, happened in 2001 in Mississauga, Ontario.

So yes, it can happen. I suspect, however, that the use of mouthwash must be immediately before the test.

So, I guess the moral of the story is if you are gonna swish, make sure to bring some wash with you in the car to convince the local cops?

Great, yet another highly unlikely but plausible thing to have to worry about.

[EdwardLost]

Also, don't brush your teeth with at bottle of Jack.

[Chessic Sense]

Originally Posted by EdwardLost

Also, don't brush your teeth with at bottle of Jack.

"Cuz when I leave for the night, I'm...going to jail."

[GilaB]

My college chemistry teacher actually did this as an in-class demonstration of a chemically-based breathalyzer test - she had a student swish with mouthwash, then take the test, which she failed.

[needscoffee]

I don't know of any alcoholic who isn't well aware of the alcohol content of mouthwashes. Or Nyquil (does it still come with its own shotglass?).