Chicago Criminal Lawyer Blog
Most people believe that a breathalyzer test is a reliable and accurate way for police to determine if a driver is intoxicated. What they don’t realize is that these devices can be fooled by completely legal, everyday products—like mouthwash or breath fresheners. In fact, a surprising number of DUI arrests in Illinois begin with a false positive triggered not by alcohol consumption, but by the alcohol content in personal hygiene products. If this happened to you in Chicago or anywhere in Illinois, the consequences are real—but so is your opportunity to fight back.
As a DUI defense lawyer with decades of courtroom experience, I’ve seen firsthand how faulty BAC readings can lead to wrongful arrests. I’ve also seen how the right legal approach can turn things around. Here’s what you need to know about how mouthwash can affect breath test results—and what to do if you’ve been charged with DUI because of it.
How Alcohol-Based Mouthwash Causes False BAC Readings
Most commercial mouthwashes contain ethyl alcohol as their primary active ingredient. Listerine, for example, has an alcohol concentration of approximately 26.9%. Other mouth rinses, breath sprays, and even some breath strips contain varying levels of alcohol, used to kill bacteria and eliminate odors.
The problem is that alcohol-based mouthwash doesn’t just kill germs—it leaves behind residual alcohol in the tissues of your mouth. This residue can last for several minutes. If you are pulled over and given a portable breath test within that timeframe, it may detect this alcohol and register a BAC far above your actual blood alcohol level.
These devices aren’t measuring how impaired you are. They’re measuring the amount of alcohol on your breath, which in the case of mouthwash, doesn’t originate in your bloodstream at all. The result? A completely sober driver may blow a 0.08% or higher and get arrested.
Portable Breath Test Results and Probable Cause for Arrest
Illinois police officers often use portable breath testing (PBT) devices at the roadside to help determine whether they have probable cause to make an arrest. These devices are not calibrated to the same standards as evidentiary breath machines and are not admissible at trial. But they are heavily relied upon to justify arrests.
When a PBT registers a BAC above 0.08%—even if it’s caused by mouthwash—it can be used as the basis to place you under arrest for DUI under 625 ILCS 5/11-501. You may then be transported to a police station where a second breath test is administered using an evidentiary device like the Intoximeter EC/IR II. If that test is done within 10–15 minutes of using mouthwash and no observation period is conducted, it too can produce a false high reading.
Even without a second test, officers may still charge you based on the PBT result and their observations—such as bloodshot eyes or nervous speech. In these cases, an arrest leads to criminal charges and a statutory summary suspension of your driver’s license.
Understanding the Legal Ramifications of a False DUI Arrest
A DUI arrest in Illinois—even for a first offense—is classified as a Class A misdemeanor under 625 ILCS 5/11-501(a). If convicted, you could face:
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Up to one year in jail
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Fines up to $2,500
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Mandatory alcohol education or treatment
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Suspension or revocation of your driver’s license
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A permanent criminal record
And if aggravating circumstances are present, such as transporting a minor or causing an accident, the charge can be elevated to a felony. This makes it all the more critical to act quickly and retain an attorney who can challenge the validity of the breath test.
How DUI Cases Based on Mouthwash Play Out in Court
In DUI cases based on false positives from mouthwash or breath sprays, the central issue is the reliability of the breath test evidence. Your attorney will review every aspect of the stop, arrest, and test administration, including:
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Whether the officer followed the mandatory 20-minute observation period
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The timing between your last use of mouthwash and the test
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The calibration and maintenance records of the testing device
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Whether the officer asked if you used any products containing alcohol
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Bodycam or dashcam footage showing your behavior and demeanor
In many cases, we can demonstrate that the breathalyzer result does not match the facts. A false reading caused by mouthwash often stands out because the driver exhibits no actual signs of impairment—no poor driving, slurred speech, or impaired motor skills. When we bring these inconsistencies to light, prosecutors may agree to reduce or drop the charges.
The Role of Expert Witnesses in Mouthwash DUI Defense
One of the strongest tools in fighting these cases is expert testimony. Toxicologists and forensic scientists can explain how residual mouth alcohol can cause an inaccurate BAC reading. They can also clarify that deep-lung air (which reflects blood alcohol content) is not the same as breath from the mouth cavity. When this scientific explanation is paired with cross-examination of the arresting officer, it can seriously undermine the prosecution’s case.
An experienced DUI lawyer will know how to locate and present the right expert witness and how to use their testimony to your advantage. We don’t just argue facts—we prove them.
Challenging the Statutory Summary Suspension
If you were arrested for DUI after a false breath test, your license will be automatically suspended starting 46 days after the arrest unless you request a hearing. This is known as a statutory summary suspension under 625 ILCS 5/11-501.1.
For a first-time breath test failure, the suspension is 6 months. For refusal, it’s 12 months. However, you have the right to file a Petition to Rescind the suspension. At that hearing, your lawyer can challenge the legality of the traffic stop, the arrest, or the administration of the test. If the court finds that the test was unreliable—such as in cases involving mouthwash—the suspension may be lifted entirely.
Common Questions From Clients About Mouthwash and DUI
Is it really possible to get a DUI from mouthwash?
Yes. Mouthwash containing alcohol can leave enough residual alcohol in the mouth to trigger a false reading on a breathalyzer, especially within 10–15 minutes of use.
Can a DUI lawyer prove I wasn’t drunk if I failed the breath test?
Yes. Your attorney can present evidence showing that the test result was false due to mouth alcohol. This may include expert testimony, video footage, and medical or product use records.
How can I fight the license suspension?
By filing a petition to rescind. Your lawyer can challenge whether the officer had probable cause to arrest you and whether the test was administered properly.
Will I have a criminal record if I’m convicted?
Yes. A DUI conviction remains on your record permanently. That’s why these cases must be fought aggressively, especially if the test result was flawed.
Can the charges be dropped if the test was wrong?
Yes. Prosecutors may reduce or dismiss DUI charges if it becomes clear that the test was invalid or misleading.
Why Early Legal Help Is So Important
The sooner you contact a DUI attorney after an arrest, the better your chances of winning your case. Breath test data can be lost, witnesses forget details, and deadlines for hearings pass quickly. Don’t wait until your first court date to get help. An attorney can begin building your defense immediately by collecting evidence, filing motions, and protecting your driving privileges.
The bottom line: if you were arrested for DUI in Illinois and the only real evidence is a breath test after using mouthwash or a breath spray, you likely have a defensible case. But you need someone who knows how to handle it.
The Law Offices of David L. Freidberg: Your Defense Starts Here
At The Law Offices of David L. Freidberg, we know how to dismantle DUI cases based on faulty breath tests. We’ve successfully defended clients in Chicago, Cook County, DuPage County, Will County, and Lake County who were arrested for DUI after using products that triggered false readings.
We provide aggressive defense, honest advice, and 24/7 availability. Whether your goal is dismissal, supervision, or avoiding a permanent conviction, we’ll fight for your best possible outcome.
Call Now – The Law Offices of David L. Freidberg Is Ready to Help
If you were arrested in Chicago for DUI, protect your future by contacting The Law Offices of David L. Freidberg. We have decades of experience handling DUI cases in Illinois. Our firm is available 24/7 to provide the legal defense you deserve.
Contact us today at (312) 560-7100 or toll-free at (800) 803-1442 for a free consultation. We’re available 24/7 to serve clients throughout Illinois, Cook County, DuPage County, Will County, and Lake County.
