A lot of what an officer reads as "impairment" can actually be a medical condition, and a lot of what a breath machine reports as a high BAC can be the byproduct of one. I am Joel Brand, and medical defenses are among the most overlooked and most powerful tools in a DUI case.
Why the medical angle gets missed
At the roadside, an officer is building a case, not taking a medical history. They see red eyes, smell something they call alcohol, watch you sway on a balance test, and they write it all down as signs of intoxication. What they almost never do is ask whether you have a condition that produces those exact signs without any alcohol at all. That gap is where a medical defense lives. When I take a careful history and match it to what the officer described, an innocent explanation often emerges for the very "evidence" the state is relying on.
Conditions that skew a breath test
GERD and acid reflux can push stomach alcohol into your mouth and spike a breath reading (the mouth alcohol problem). Diabetes and low-carb (ketogenic) diets produce acetone and isopropyl-type compounds that some breath machines can misread as alcohol. Hypoglycemia, or low blood sugar, can mimic intoxication outright. Even prolonged fasting can put the body into ketosis and generate compounds a breath machine may pick up. None of these reflect the ethanol the test is supposed to be measuring.
Diabetes and hypoglycemia
Diabetes deserves its own mention because its symptoms read like a textbook DUI. A diabetic experiencing low blood sugar can appear confused, slur their speech, sweat, lose coordination, and behave erratically, exactly what an officer expects from a drunk driver. On top of that, diabetic ketoacidosis produces acetone on the breath that some devices can register as alcohol. A diabetic stopped while having an episode can fail both the observation test and the breath test for reasons that have nothing to do with drinking. See the dedicated diabetes and DUI article.
Conditions that mimic impairment
Fatigue, neurological and inner-ear disorders, old leg and back injuries, anxiety, and even allergies can produce red eyes, slurred speech, poor balance, and a shaky performance on field sobriety tests, none of which proves alcohol impairment. Vertigo and inner-ear problems destroy balance. Neurological conditions can affect speech and eye movement, which matters for the HGN eye test. The officer's "objective signs" often have an innocent medical explanation that the report never considered.
Speech, eyes, and balance have many causes
Three of the most common "signs of intoxication" in a police report are slurred speech, bloodshot or watery eyes, and unsteadiness. Each has a long list of innocent causes. Slurred or thick speech can come from fatigue, a stroke history, dental work, a speech impediment, or medication. Red, watery eyes can be caused by allergies, contact lenses, smoke, crying, or simply being awake at 2 a.m. Unsteadiness can stem from injury, obesity, age, inner-ear disease, or the uneven roadside itself. When I can tie the officer's observations to a documented condition, those "signs" stop pointing toward alcohol.
Medications and prescriptions
Many lawful prescription and over-the-counter medications cause drowsiness, slowed reactions, or eye movements that an officer may misattribute to alcohol, and some can interact with the testing process. This is its own area of defense, but it overlaps heavily with the medical picture, and disclosing your full medication list to your attorney (never to the officer at the scene) is often important.
The keto and low-carb diet problem
One of the more surprising medical defenses involves diet. When the body burns fat instead of carbohydrates for fuel, as happens on a strict ketogenic or low-carbohydrate diet, during fasting, or in uncontrolled diabetes, it produces ketones, including acetone. The body converts some of that acetone into isopropyl alcohol, and certain breath-testing devices are not specific enough to distinguish it from the ethanol in alcoholic drinks. A sober person on a strict keto diet can, in some circumstances, register a positive or inflated breath reading. It sounds far-fetched, but it is well documented in the forensic literature, and it is exactly the kind of explanation an officer at the roadside would never think to consider.
Why these defenses are so persuasive
Medical defenses are powerful for a simple reason: they do not just poke a hole in the state's evidence, they offer the judge, prosecutor, or jury an affirmative, innocent explanation for everything the officer saw and the machine recorded. Instead of arguing only that the state cannot prove its case, a medical defense tells a complete alternative story that fits the facts. When that story is backed by medical records and, where needed, expert testimony, it is genuinely hard for the prosecution to overcome, because the burden remains on them to prove impairment by alcohol beyond a reasonable doubt.
Document the condition early
If a medical condition may have played a role in your arrest, the time to document it is now. Gather records from your doctor, note your current prescriptions, and preserve anything that establishes the diagnosis and its symptoms. Conditions that flare and subside, like reflux or low blood sugar, are best supported by a contemporaneous medical record rather than a description offered months later. The sooner I have that documentation, the sooner I can use it to shape the case in your favor.
How I raise it
I gather your medical records, identify which condition fits the facts, and where needed bring in a medical or toxicology expert to explain it to the prosecutor or jury. A well-documented medical explanation can persuade a prosecutor to reduce or dismiss a charge before trial, and it can create reasonable doubt with a jury if the case goes that far. It pairs with the rising BAC and calibration defenses, and it is relevant at the DMV hearing as well. See my top DUI defenses.
Think this applies to you? Let's find out.
Whether this defense fits depends on the specific records and facts of your stop, which is exactly what I review. Use the free case analysis on this page, or call me directly at (888) 271-6644. I answer my own phone, 24/7.
From the DUI blog: Arrested for DUI When a Medical Episode Made You Look Impaired in California.