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How Mouthwash and Breath Fresheners Can Trigger False BAC Readings in Illinois
Chicago DUI Defense Lawyer – The Law Offices of David L. Freidberg
Chicago is a city full of activity—entertainment, nightlife, long commutes, and constant interaction with law enforcement on busy roads like Lake Shore Drive, I-90/94, and countless residential neighborhoods. In such an active metro, DUI enforcement is taken seriously. But what happens when your breath test result is skewed not by alcohol consumption, but by the use of something as common as mouthwash or a breath spray? It happens more often than most people realize. And if you’ve been arrested for DUI because of a false positive reading caused by a breath freshener, you need to understand what went wrong—and why hiring a defense attorney could make the difference between a conviction and a cleared name.
How Mouthwash and Breath Fresheners Can Lead to False DUI Results in Illinois
Many commercial mouthwashes and breath freshening sprays contain alcohol—some of them as much as 20–30%. These products are designed to leave your breath smelling clean but leave behind traces of ethanol. Portable breath testing devices, also called PBTs or roadside breathalyzers, are designed to detect the presence of alcohol in the breath, but they cannot distinguish between deep lung alcohol (from actual alcohol consumption) and residual mouth alcohol (like what remains from mouthwash).
When you use a mouthwash and are pulled over shortly afterward, a PBT may register a high BAC even if you haven’t consumed alcohol at all. This reading can be used to support probable cause for arrest. In most DUI investigations, that’s all an officer needs. From there, you’re arrested and charged under 625 ILCS 5/11-501, Illinois’ DUI statute.
The law doesn’t require a failed test to arrest someone. Even if the only basis is a PBT reading and officer observations like red eyes or nervous behavior, a DUI charge can proceed. That’s why mouthwash-induced false positives matter so much—they can form the foundation of a criminal prosecution when no actual impairment exists.
Understanding DUI Law in Illinois and How False BAC Readings Fit In
In Illinois, DUI is defined under 625 ILCS 5/11-501 as driving or being in actual physical control of a vehicle while:
– Having a BAC of 0.08% or greater
– Being under the influence of alcohol to a degree that renders you incapable of driving safely
– Having any amount of a controlled substance in your body
– Being under the combined influence of alcohol and drugs
It’s important to note that prosecutors do not need a 0.08% reading to proceed. If an officer testifies that you showed signs of impairment and a PBT showed alcohol, that can be enough for a charge. A false high BAC from mouthwash may push your result above 0.08%, making it harder to fight without proper legal defenses.
A first offense DUI in Illinois is typically charged as a Class A misdemeanor, punishable by up to 364 days in jail and fines up to $2,500. However, if aggravating factors are present—such as driving with a child in the car or being involved in a crash—the charge may be upgraded to a felony under 625 ILCS 5/11-501(d). That’s why even an innocent mistake like using Listerine before driving can lead to life-altering consequences.
From Stop to Arrest: How DUI Cases Begin and Why Mouth Alcohol Can Trigger Charges
Most DUI cases in Chicago begin with a traffic stop. An officer may claim to observe lane drifting, a broken tail light, speeding, or another minor violation. Once you’re stopped, they look for indicators of alcohol use—odor, slurred speech, red eyes, or fumbling for your license. If they suspect DUI, they will ask questions and request that you perform field sobriety tests.
If you’ve recently used a mouthwash or breath spray, and they administer a PBT, that device may give a reading far above 0.08%, even if you’re completely sober. Portable devices are notoriously unreliable and not admissible in court in Illinois—but they are commonly used to establish probable cause.
Once arrested, you may be asked to submit to a breath, blood, or urine test at the police station. While evidentiary breath tests are more accurate than roadside devices, even these can be affected by residual mouth alcohol if conducted too soon after a mouthwash was used. Without a lawyer, these technicalities often go unexplored, and false results can lead to a conviction.
What Happens After You’re Arrested and Charged With DUI in Chicago
If you’re arrested in Chicago, you’ll likely be processed at a local police station and then appear at the Daley Center or another Cook County courthouse for arraignment. You’ll face a summary suspension of your driver’s license under 625 ILCS 5/11-501.1, regardless of whether you’re eventually convicted. This suspension starts on the 46th day after arrest unless you file a petition to rescind.
You’ll also be formally charged with DUI and given a court date. During the early stages, your attorney can request discovery, review video footage, analyze police reports, and evaluate whether your BAC result may have been artificially inflated by non-alcoholic consumption.
How the Trial Process Works for DUI Cases in Illinois
DUI cases in Illinois typically proceed through a series of court appearances, starting with arraignment and followed by status hearings, motion hearings, and a possible trial. A DUI defense attorney can file motions to suppress breath results or get evidence excluded due to improper testing, chain of custody issues, or invalid probable cause.
At trial, the prosecution must prove beyond a reasonable doubt that you were impaired or had a BAC of 0.08% or more while driving. If your BAC reading came solely from mouthwash, your attorney can present scientific testimony, cross-examine the officer, and challenge the machine’s accuracy.
What Evidence Is Collected in These Cases?
Law enforcement builds DUI cases using bodycam footage, dashcam video, field sobriety test performance, breath test results, and officer observations. If you told the officer you had just used mouthwash or if video shows you spitting something out before the test, this can support your defense.
Other critical evidence includes calibration records for the breath device, video from the station, and the time between mouthwash use and the test. Because mouth alcohol dissipates quickly—usually within 15 minutes—a test given too soon can register artificially high.
Why a DUI Lawyer Is Vital When Breath Test Results Are Involved
If your arrest was based on a faulty PBT reading or a misunderstood interaction with the police, you need a DUI lawyer to push back on that evidence. Without representation, you risk being convicted based on flawed science or procedural errors.
A lawyer can:
– File a petition to rescind your license suspension
– Suppress unreliable BAC results
– Challenge the timing and administration of the test
– Introduce scientific evidence about false positives from mouthwash
– Negotiate for reduced charges or court supervision
Legal Defenses in False BAC DUI Cases
Several defenses may apply in DUI cases involving false breath test results:
– The breath test was conducted too soon after using mouthwash
– The test device was not properly calibrated
– The officer lacked probable cause for the arrest
– You did not actually consume alcohol, and there is no supporting evidence beyond the BAC reading
– Chain of custody issues or errors in documentation
These defenses can be raised in pretrial motions or at trial. In many cases, prosecutors will reduce or drop charges if it becomes clear the evidence is unreliable.
Choosing a DUI Defense Lawyer in Chicago
In DUI cases where breath test accuracy is in question, you need a defense lawyer who understands both the science and the courtroom. Look for someone who regularly handles DUI cases in Cook County and has experience challenging breathalyzer results.
Ask whether the lawyer has fought breath machine reliability in court, how they handle summary suspension hearings, and whether they’ll be the one representing you in court.
Questions to Ask in a DUI Consultation
– Have you handled cases involving false BAC readings?
– Can we fight the license suspension even if I failed the test?
– What defenses do you see in my case?
– Will you handle the case personally or assign it to another attorney?
– How often do you try DUI cases in Cook County?
Chicago DUI FAQs: Mouthwash and False Positives
Can mouthwash really cause a false positive on a breathalyzer?
Yes. Many mouthwashes contain high percentages of alcohol. If used shortly before a test, the alcohol can linger in your mouth and result in a high BAC reading on a portable breathalyzer.
Will the judge believe I wasn’t drinking if I used mouthwash?
That depends on the evidence. If your attorney can show you used mouthwash before the test and the timing lines up, it’s a viable defense. Lab testing and expert testimony can also help.
How long does mouth alcohol stay in the mouth?
Residual alcohol from mouthwash typically disappears within 10 to 15 minutes. If a test is conducted too quickly after use, the result may not reflect actual impairment.
Do police have to wait before giving a breath test?
In Illinois, officers are supposed to observe a driver for 15–20 minutes before administering an evidentiary breath test. If they don’t, and you used mouthwash, that can be used to challenge the result.
What’s the penalty for a first-time DUI?
Up to a year in jail, fines up to $2,500, and license suspension. You may be eligible for court supervision if it’s your first offense, but false positives still need to be aggressively defended.
Can a lawyer get the case dropped if the test was wrong?
It’s possible. If your defense attorney can demonstrate that the BAC result was inaccurate due to mouthwash or device error, the prosecutor may dismiss the case or reduce the charge.
Why Choose The Law Offices of David L. Freidberg
At The Law Offices of David L. Freidberg, we take breath test challenges seriously. With decades of experience defending DUI cases in Chicago and surrounding counties, we’ve helped clients avoid wrongful convictions based on flawed breathalyzer results—especially when caused by mouthwash or similar products.
We know how to challenge these cases with science, expert testimony, and proven courtroom strategy. Our goal is always to protect your rights, your license, and your future.
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.