Can Mouthwash Affect a Breathalyzer Test in Minnesota?
Using mouthwash before getting behind the wheel might seem harmless—until it causes you to fail a breathalyzer test. Can alcohol-based mouthwash lead to a false positive for DUI in Minnesota?
Yes, mouthwash can produce a false positive breathalyzer result if it contains alcohol, even if you haven’t consumed any alcoholic beverages. The alcohol residue can linger in your mouth and trick the breath test into detecting a higher blood alcohol concentration (BAC) than is actually present in your body.
At Gerald Miller, P.A., our DWI defense team has successfully challenged countless breathalyzer results influenced by mouthwash, medications, and other non-intoxicating sources of alcohol. If you’ve failed a test you believe was inaccurate, we can help protect your rights and fight the charge. Police officers rely on breathalyzer results, and errors in testing can lead to serious consequences such as car impoundment, license suspension, or even a DUI conviction if not properly challenged.
Introduction to Breathalyzer Tests
Breathalyzer tests are a primary tool used by law enforcement to determine if a driver is over the legal alcohol limit. When suspected of DUI, officers administer a breath test that estimates blood alcohol concentration (BAC) by analyzing alcohol in the breath, helping to identify impaired drivers and ensure road safety.
However, breathalyzers can produce false positives due to mouth alcohol—alcohol lingering in the mouth from mouthwash, breath sprays, or certain medications. This residual alcohol can cause the device to register a higher BAC than what is actually in the bloodstream, leading to inaccurate readings and potential DUI charges even if the driver hasn’t consumed alcohol. Understanding these factors is essential to recognizing how everyday products may affect breathalyzer results.
Understanding Blood Alcohol
Blood alcohol concentration (BAC) measures the amount of alcohol in a person’s bloodstream. Alcohol is absorbed into the blood and detected through breath, blood, or urine tests. Breathalyzer tests estimate BAC by measuring alcohol in the breath, providing a quick, non-invasive way for law enforcement officers to determine if a driver is over the legal limit.
In Minnesota and most states, the legal BAC limit is 0.08%. Exceeding this can lead to severe penalties like fines, jail time, and license suspension. However, factors such as alcohol consumed, body weight, metabolism, medical conditions, environmental factors, and substances like mouthwash can affect BAC readings and cause false positives.
Because non-beverage alcohol sources can cause inaccurate readings, anyone facing DUI charges should seek experienced legal defense. A skilled attorney can challenge questionable breathalyzer results influenced by medical or environmental factors, helping protect your rights and ensure a fair process.
How Can Mouthwash Cause a False Positive on a Breathalyzer?
Most commercial mouthwashes contain high levels of ethyl alcohol (ethanol)—sometimes over 25% alcohol by volume, comparable to some liquors. This alcohol can coat your mouth, gums, and tongue, leaving trace amounts that affect breathalyzer results.
Breathalyzers detect alcohol in deep lung air (alveolar air) to estimate blood alcohol content. However, residual mouth alcohol can cause falsely high readings. Dentures may trap alcohol in the mouth, increasing false positive risks. Medical conditions like acid reflux can also release alcohol vapor into the mouth, further skewing results. The device cannot distinguish between alcohol from the lungs and mouth alcohol.
In short, mouth alcohol tricks the breathalyzer into thinking you’re intoxicated—even when you’re not.
Common Products That May Trigger False Positives
Mouthwash isn’t the only item that can interfere with breath tests. Other alcohol-containing products include a wide range of items that contain alcohol and can interfere with breath tests: Using non-alcoholic mouthwash can prevent false positive readings.
- Breath sprays and mints (e.g., Binaca)
- Certain cold and cough syrups (some of which contain enough alcohol to trigger a false positive)
- Asthma inhalers
- Chewing tobacco or gum
- Sorbitol-based sugar-free candies
- Alcohol-based hand sanitizers (in enclosed spaces)
Unlike an alcoholic beverage, which is consumed for its alcohol content, these products may still contain alcohol and can impact breath test results. Even non-beverage products can cause elevated BAC readings or device failures.
There are many such products on the market today, increasing the risk of accidental false positives.
What Happens If You Fail a Breathalyzer Because of Mouthwash?
In Minnesota, a BAC of 0.08% or higher is considered legally impaired. But a mouthwash-influenced false positive could put you over the limit even if you’re stone-cold sober. Failing a breathalyzer due to a false reading can have serious consequences for a person who has not consumed alcohol, including legal trouble and loss of driving privileges.
If you’re pulled over and submit to a breath test shortly after using mouthwash:
- You may be tested and receive a positive result due to mouthwash, not actual intoxication.
- Officers may arrest you based on that result.
- You’ll likely face DWI charges and a license suspension unless the result from the alcohol test is disproven.
Your Rights in This Situation
You have the right to:
- Request a second breathalyzer after 15–30 minutes.
- Challenge the accuracy of the test in court.
- Refuse field sobriety tests (though you may face consequences).
- Speak with an attorney before agreeing to chemical testing.
These rights are especially important if you believe you have received an unfair breathalyzer result.
Time is critical. Alcohol from mouthwash typically dissipates within 10–15 minutes. A retest during that window can show a much lower—and more accurate—BAC level.
Challenging an unfair breathalyzer result is crucial to protecting your rights in a potential DUI case.
Does Mouthwash Affect Ignition Interlock Devices (IIDs)?
Yes. If you are part of Minnesota’s Ignition Interlock Device Program, using alcohol-based mouthwash before driving can cause the IID to lock your vehicle and record a violation.
IIDs are calibrated to detect very low levels of alcohol—often as low as 0.02%—to ensure compliance. Like a police breathalyzer, an IID is designed to detect alcohol, but it is especially sensitive to alcohol vapors that may linger in the mouth. This sensitivity can lead to a false positive reading if alcohol vapors from mouthwash are present.
What To Do If Mouthwash Triggers Your IID
- Wait 15–20 minutes before blowing after using mouthwash.
- Rinse your mouth with water and breathe fresh air.
- Avoid alcohol-based products entirely, including mouthwash and breath spray.
- If you fail, many devices will prompt a retest in 5–10 minutes. Take that opportunity to produce a clean sample.
For example, someone who used mouthwash was tested by their IID just a few minutes later and received a false positive result. This highlights the importance of waiting before testing to avoid inaccurate readings.
You should also immediately report the incident to your IID program provider. Documenting the use of mouthwash and the result can help avoid additional penalties or license complications.
Can You Be Charged With DWI If Mouthwash Caused the Test Result?
Yes—at least initially. Police often rely on breath test results at the scene to justify arrests. However, a skilled DWI defense attorney can challenge that result as invalid or misleading. This is especially important if you have not consumed alcohol but still failed the test. Consulting a DUI lawyer is crucial to contest the charges and protect your rights.
In some cases, you may request a blood test, which is considered more accurate for measuring blood alcohol concentration.
Defenses We May Use Include:
- Mouth alcohol contamination (e.g., from mouthwash or breath spray)
- False positive breath tests can occur if a person is tested shortly after using mouthwash or other alcohol-containing products, leading to inaccurate results.
- Improper wait period before testing (officers must wait 15 minutes)
- Failure to administer multiple tests
- Malfunction or miscalibration of the breathalyzer
- Unlawful stop or detention
Remember: A failed breath test does not equal guilt. The law requires proof beyond a reasonable doubt.
How We Defend Clients Against False Positive Breathalyzer Charges
At Gerald Miller, P.A., we begin every DWI defense by scrutinizing:
- The type of breathalyzer used
- Whether the 15-minute observation period was followed
- Whether the officer asked if the person was recently tested after using mouthwash or medication
- Retest timing and results
- Other field sobriety indicators (or lack thereof)
We may also bring in toxicology experts to challenge the scientific validity of the breath sample. In many cases, we can have charges reduced or dismissed altogether.
If you are a person who believes you were unfairly tested and charged due to mouthwash use, contact us today to schedule a free consultation.
What Should You Do After a Failed Test Caused by Mouthwash?
If you believe your breath test result was due to mouthwash, take the following steps immediately: A false positive result could put your car and driving privileges at risk.
- Tell the officer on scene that you used mouthwash.
- Request to be tested again after a short delay (ideally 15–30 minutes).
- Document the brand, time, and amount of mouthwash used.
- Request legal representation immediately.
- Avoid making statements or assumptions—they can be used against you.
Every minute counts. The sooner you contact a Minnesota DWI attorney, the more options you have.
Why Choose Gerald Miller, P.A. for Your Minnesota DWI Defense?
- Over 40 Years of Proven Criminal Defense Results
- Thousands of DWI Cases Handled Across Minnesota
- Deep Knowledge of Breathalyzer and IID Challenges
- Aggressive Strategies to Suppress Illegitimate Evidence
- 24/7 Access to a Defense Team That Works for You
- Experienced DUI lawyers dedicated to contesting false positive breathalyzer results and defending against DUI penalties
When your license, job, and freedom are on the line, don’t leave your defense to chance. Trust a team that’s been fighting—and winning—for Minnesotans since 1979.
Schedule Your Free Case Evaluation Today
Failed a breathalyzer after using mouthwash? Don’t let a false positive become a permanent criminal record. The sooner we get involved, the stronger your defense will be.
Call 612-341-9080 Request your free DWI defense consultation. Schedule your free consultation today to discuss your DUI case and learn how we can help defend against faulty breathalyzer results.
Further Reading:
DWI Defense Based on Challenging Breath Test
How Cigarettes Could Create False Breathalyzer Results in DWI Arrests
How To Beat a DUI Charge in Minnesota
Resources:
- Minnesota Statutes § 169A – Driving While Impaired
- NHTSA – Breath Alcohol Testing Devices
- NIH – Alcohol Content in Common Mouthwashes
