Can Mouthwash Affect Breathalyzer Results?

When you're charged with drunk driving, it can have a major impact on your life. Simply getting to and from work may become a major hassle. That's why it's important to speak with a DUI defense lawyer familiar with Phoenix and Arizona drunk driving laws. An attorney's experience with DUI cases can be crucial for you as you attempt to get charges dropped.

The fact of the matter is that there are many potential flaws when a police officer measures sobriety. We have talked about DUI breath test problems and false positives many times. Right now, we want to address a popular topic about breathalyzer tests. Some people say that using mouthwash can cause you to fail a breathalyzer. Let's look into the issue in more detail.

How a Breathalyzer Works

A breathalyzer is a device that's used to estimate a person's blood alcohol content (BAC) by taking a breath sample. A person blows into the device, which then notes the presence of alcohol in that person's breath.

Are Breathalyzers Always Accurate?

No. In fact, there are many flaws inherent in breath tests.

Think about it: if someone is trying to measure the alcohol content of your blood, why would they use your breath to do this? Breath and blood are not the same, which can lead to people who are legally sober being charged with drunk driving.

There are potential contaminants in the mouth and lungs that could affect the overall results of a breathalyzer test. This means a false positive and an unjust charge of drunk driving.

Residual Alcohol in the Mouth

One of the key flaws of breathalyzer tests involves residual alcohol in a person's mouth. Whenever someone has an alcoholic beverage, some of that alcohol can remain in the mouth rather than being swallowed. The alcohol can wind up in someone's saliva, for instance, or under the tongue or in between the teeth. If there is alcohol in the mouth, the presence of this alcohol can lead to a higher breathalyzer reading than normal.

Keep in mind, however, that residual alcohol in the mouth does not last that long. It will have disappeared on its own within 20 minutes or so. However, that may be enough time to throw off a breathalyzer depending on when a person is pulled over and the test is administered.

The Alcohol Content of Mouthwash

Some mouthwashes such as Listerine contain alcohol, which helps kill oral bacteria and keep the mouth fresh. If you rinse you mouth out before heading out the door and are pulled over soon after you started driving, there is a chance that you may blow a .08 BAC simply because of the presence of residual alcohol in your mouth.

Certain lozenges, medications, and cough drops may also have a similar effect on a breathalyzer test, though maybe not as pronounced as mouthwash.

So Is It True That Mouthwash Affects Breathalyzers?


This is not just an urban legend or some unsubstantiated rumor on the internet. While the circumstances are very narrow when it comes to mouthwash affecting a breathalyzer test, the issue may arise. Should the matter arise, it's important to have a skilled DUI defense attorney on your side to help ensure your rights are respected and you receive a fair hearing. It may be possible to get your charges dropped.

Learn More About DUI Legal Defense

For more information about your legal rights and options following a drunk driving charge, be sure to contact an experienced DUI defense attorney today. Our legal team will fight for you in your time of legal need.

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