Yes—and this is one of the most underrated defense angles in DWI cases. Certain medications can make you look intoxicated when you’re not, and specific health conditions can cause a breathalyzer to spit out a BAC reading that’s significantly higher than what’s actually in your blood.
Understanding how this works matters whether you’re someone who takes daily medication and wants to know the risk, or someone who just got a BAC reading that doesn’t match how much you actually drank.
How a Breathalyzer Can Get It Wrong
Before getting into the specific conditions, it helps to understand the basic weakness at the core of every breath test.
A breathalyzer doesn’t directly measure your blood alcohol. It measures alcohol vapor in your breath and then uses a mathematical formula to estimate what your blood alcohol content should be. That conversion relies on a set of assumptions about your body—assumptions that don’t hold true for everyone.
When something disrupts the normal path of breath from your lungs to the machine—whether it’s a medical condition pushing alcohol vapors up from your stomach or a substance in your mouth that the machine misreads as ethanol—the result can be a falsely inflated BAC that doesn’t reflect reality.
This is exactly why breathalyzer results are challengeable in court, and why a defense attorney’s first move is always to dig into the testing procedure and the person behind the number.
Medical Conditions That Can Inflate Breathalyzer Readings
GERD and Acid Reflux
Gastroesophageal Reflux Disease (GERD) is probably the single most significant medical condition when it comes to false breathalyzer readings. Here’s why: GERD causes stomach contents—including any undigested alcohol—to flow backward up through the esophagus and into the mouth. The breathalyzer is supposed to measure deep lung air only, but when alcohol vapors from the stomach contaminate that breath sample, the machine reads them together and produces an artificially high number.
This is known as the “mouth alcohol” problem, and it’s serious enough that officers are required to conduct a 15 to 20 minute observation period before administering the test—specifically to watch for burping, belching, or regurgitation. But here’s the catch: with chronic GERD, reflux can happen silently. You might not even feel it, the officer might not see it, and the observation period does nothing to prevent it.
Acid reflux as a breathalyzer defense is grounded in well-established science and has been recognized by courts in New York DWI cases.
Diabetes
People with diabetes—particularly those with poorly controlled blood sugar—can produce elevated levels of acetone through a metabolic process called ketoacidosis. The problem is that some breathalyzer models cannot reliably distinguish between acetone and ethanol (drinking alcohol). The National Highway Traffic Safety Administration (NHTSA) has acknowledged that diabetics can have acetone levels hundreds of times higher than non-diabetics, and this acetone can register as alcohol on certain breath testing instruments.
Ketogenic and Low-Carb Diets
Even without diabetes, people following strict keto or low-carb diets can enter a state of ketosis that produces acetone in their breath. The mechanism is the same: the body burns fat for fuel, produces ketones, and those ketones can trick the breathalyzer into reading a BAC that doesn’t exist. It’s a real problem for anyone on a popular diet who has a couple of drinks and then gets tested.
Medications That Can Cause Problems
Medications affect breathalyzer situations in two distinct ways. Some contain alcohol that directly inflates the reading. Others cause physical symptoms that make you appear intoxicated, leading to an arrest in the first place.
Medications Containing Alcohol
Several common over-the-counter products contain enough alcohol to affect a breath test:
| Product Type | How It Affects the Test |
|---|---|
| Cough syrups (e.g., NyQuil) | Contain alcohol that lingers in the mouth and throat |
| Mouthwashes (e.g., Listerine) | Up to 26% alcohol content; residual mouth alcohol |
| Breath sprays and fresheners | Alcohol-based formulas leave residue |
| Cough drops with menthol | Can produce elevated readings |
| Herbal supplements/tinctures | Often alcohol-based liquid formulations |
These products are especially dangerous if used shortly before a traffic stop, because the alcohol sits in your mouth and throat rather than coming from your bloodstream. The breathalyzer doesn’t know the difference.
Medications That Mimic Intoxication
A separate category of medications won’t directly inflate your BAC number, but they can cause symptoms that make an officer believe you’re drunk—and that belief leads to an arrest, field sobriety tests, and ultimately a chemical test. These include:
- Antihistamines and allergy medications (drowsiness, slowed reactions)
- Prescription painkillers and muscle relaxants (slurred speech, poor coordination)
- Anti-anxiety medications and sedatives (unsteadiness, confusion)
- Sleep aids (grogginess, impaired motor function)
- Some blood pressure medications (dizziness, lightheadedness)
If you’re taking any of these and get pulled over, the officer sees what looks like a classic impaired driver. You might fail field sobriety tests not because you’ve been drinking, but because your medication affects balance, coordination, and cognitive speed. That’s an important distinction—and one your attorney needs to know about.
It’s also worth noting: if a medication impairs your ability to drive, you can be charged with DWAI-Drugs regardless of whether the drug is legal. This applies to prescription medications and even over-the-counter drugs combined with small amounts of alcohol.
Other Factors That Can Contaminate a Breath Test
Beyond diagnosed medical conditions and medications, several other factors can throw off breathalyzer accuracy:
- Dental work — Dentures, bridges, caps, and recent dental procedures can trap alcohol in tiny crevices in the mouth, creating residual mouth alcohol that inflates the reading
- Recent vomiting or burping — Brings stomach contents (including alcohol) into the mouth and throat
- Smoking — Can introduce compounds that interfere with the chemical reaction inside the breathalyzer
- Environmental exposure — Painters, auto body workers, and others exposed to acetone or similar chemicals on the job can carry those compounds into a breath test
The 15-20 Minute Observation Period: Your First Line of Defense
New York requires officers to continuously observe a DWI suspect for 15 to 20 minutes before administering the official chemical breath test at the station. During this time, the officer is supposed to watch for anything that could introduce mouth alcohol—burping, vomiting, eating, drinking, or putting anything in your mouth.
Under Vehicle and Traffic Law § 1194, the chemical test must also be administered within two hours of arrest to be admissible. If the officer didn’t properly follow the observation protocol—or if there’s video showing you burping or experiencing visible reflux during that window—the entire test result becomes challengeable.
What This Means for Your Defense
If you have a medical condition like GERD, diabetes, or any condition that affects your metabolism, or if you were taking medications at the time of your arrest, this information is critical to your defense. Your attorney needs to know about it immediately.
A defense built on medical interference with the breathalyzer isn’t just theoretical—it’s grounded in well-established science and recognized by courts. When combined with other defense strategies like challenging the machine calibration, the legality of your arrest and what followed, or a rising BAC argument, a medical condition defense can significantly weaken the prosecution’s case or lead to reduced charges.
The bottom line: a breathalyzer number is not the final word on your case. It’s a starting point—and when your body, your health, or your medications are factored in, that number might not mean what the prosecution thinks it means.
Disclaimer: This overview is for informational purposes only and does not constitute legal advice. Every case is unique—contact the DWI TEAM defense attorneys for personalized guidance.
