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A Medical Condition — Not Alcohol — May Be Behind Your DUI Arrest

Diabetes, GERD, acid reflux, ketosis, and a range of neurological conditions can all mimic the signs of intoxication, throw off field sobriety performance, and even trigger false-high readings on a breath test — all without a drop of alcohol involved.

California criminal defense attorney David Chesley has successfully defended DUI charges by establishing that observed symptoms, field sobriety test performance, and breath and blood test results were caused or affected by a medical condition rather than alcohol or drugs — in criminal courts across every county in California. A DUI charge requires proof of impairment by alcohol or drugs or a BAC of 0.08% or higher at the time of driving. When a medical condition explains the evidence, the prosecution's case fails. Every medical defense is identified and developed with expert support from day one. Build your defense now.

_{Reviewed by David S. Chesley, Esq., Managing Attorney — Law Offices of David S. Chesley, Inc.}

IF A MEDICAL CONDITION MAY HAVE PLAYED A ROLE, START HERE

• Do not make statements about your medical history or medications without counsel — they can be used against you, and the specific framing of medical condition evidence must be developed with experienced counsel before any disclosure is made
• Document your medical history immediately — every diagnosed condition, every medication you are taking, every symptom you experienced on the day of the arrest, and any relevant medical appointments; this information is most complete and most accurate right now
• Gather your medical records — physician notes documenting the diagnosis and treatment, pharmacy records, and any laboratory results relevant to the condition's status on the date of the arrest
• Contact experienced DUI defense counsel immediately — expert forensic toxicology and medical analysis requires prompt record review; the medical defense is most complete when the expert has access to the most current and most detailed records available

Call now for a free, confidential consultation — available 24/7.
📞 (800) 755-5174

WHY MEDICAL CONDITIONS CREATE POWERFUL DUI DEFENSES

Medical conditions can:

• Produce symptoms mimicking alcohol impairment — slurred speech, unsteady gait, confusion, glassy eyes, and inappropriate responses
• Affect field sobriety test performance — balance, coordination, gait, and eye movement functions directly measured by the standardized tests
• Cause false or elevated breath test readings — mouth alcohol from GERD and acid reflux; ketone interference from diabetes and ketosis

This directly challenges both VC § 23152(a) — impairment — and VC § 23152(b) — the per se BAC charge.

Quick Comparison of Common Medical Defenses:

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KEY MEDICAL CONDITIONS AND DEFENSES — HOW EACH WORKS

Diabetes: Hypoglycemia, Hyperglycemia, and Ketosis All Come Into Play

Diabetes is one of the most powerful and most commonly applicable medical defenses in DUI cases, since it can affect a prosecution in three ways at once: producing symptoms that mimic impairment, throwing off field sobriety test performance, and creating false or elevated breath test readings.

Hypoglycemia and how easily it's mistaken for intoxication: a diabetic with abnormally low blood glucose can present symptoms virtually indistinguishable from being drunk — slurred speech, confusion, disorientation, unsteady gait, glassy eyes, inappropriate emotional reactions, trouble following instructions. Without a blood glucose test, which officers almost never administer, there's no way to tell hypoglycemia apart from alcohol impairment in the field. Someone who looked drunk but was actually mid-hypoglycemic-episode wasn't impaired by alcohol at all — they were experiencing a medical event. Every symptom the officer logged gets checked against the known hypoglycemia profile and presented through expert testimony as exactly that.

Hyperglycemia and ketone interference on breath tests: elevated blood glucose produces ketone bodies as a byproduct of fat metabolism, and the ketone acetone is chemically close enough to isopropanol that some breath testing devices misread it as ethanol — producing a falsely elevated result that has nothing to do with actual blood alcohol. Whichever specific device was used, along with its fuel cell or infrared spectroscopy technology and its known susceptibility to acetone interference, gets analyzed to determine how much that ketone production could have skewed the result.

The fruity-breath problem: a diabetic in ketosis often has acetone-scented breath that an officer unfamiliar with the condition can easily mistake for alcohol. Combined with other diabetic symptoms, that smell alone can lead an officer to conclude alcohol impairment when the entire picture is really a medical condition.

GERD and Acid Reflux: How Stomach Contents Contaminate a Breath Sample

GERD and acid reflux rank among the most important medical defenses in breath test DUI cases, because they can directly inflate a breath test reading by introducing mouth alcohol into the sample.

Here's the actual mechanism: GERD and acid reflux push stomach contents — including any alcohol present — back up into the esophagus and sometimes the mouth. If that happens during or right before a breath test, that mouth alcohol gets drawn into the device right alongside the deep-lung air the test is actually supposed to measure. The device can't tell the difference between accurate alveolar alcohol and contaminating mouth alcohol, so the reading comes back artificially high.

This connects directly to the Title 17 observation period: that mandatory 15-minute window exists specifically to let mouth alcohol — from burping, belching, or reflux — dissipate before testing. Where a GERD defendant had a reflux event during that window, and the officer either missed it or failed to restart the clock, two defenses converge at once: GERD explains why mouth alcohol was present, and the Title 17 violation explains why the required safeguard against it failed. Together, they're stronger than either one alone.

This defense is strongest with a documented, physician-treated GERD diagnosis, reflux symptoms on the day of arrest, and a meaningful difference between the two breath test results — potentially reflecting one sample getting contaminated by a reflux event and the other not.

Ketosis: Not Just a Diabetes Issue — Diet and Fasting Cause It Too

Ketosis isn't exclusive to diabetics — it's a metabolic state that can come from very low-carb diets (including the popular ketogenic diet), extended fasting, significant caloric restriction, or certain medical conditions. When the body is in ketosis, it produces ketone bodies, including acetone and isopropanol, as metabolic byproducts.

How much of a problem this is depends entirely on the specific device. Some instruments, particularly ones using broad-spectrum infrared spectroscopy, can't reliably distinguish ethanol from the ketone-related compounds acetone and isopropanol, and may misread them as ethanol. The actual degree of interference comes down to the specific instrument used, how much ketone the defendant was actually producing based on how long they'd been in ketosis and how strict the diet was, and the concentration of those compounds in the breath at the time of the test. The specific device gets checked for its known susceptibility, and the expert's testimony ties the defendant's specific ketone level to that device's specific measurement quirks.

Neurological Conditions: When the Test Wasn't Built for This Body

Field sobriety tests were validated on subjects with no medical conditions, no physical disabilities, and normal neurological function. Someone with a neurological condition taking that same test is, effectively, taking a test that was never built for them — and the results have no established connection to alcohol impairment in that context.

Inner ear disorders and balance tests. The one-leg stand and walk-and-turn tests both measure balance — specifically the ability to hold stability while doing a divided-attention task — and balance is governed by the vestibular system in the inner ear. Someone with Meniere's disease, labyrinthitis, or vestibular neuritis can't reliably perform balance-based tests regardless of alcohol. When an officer scores that inability as impairment, they're really just observing a vestibular symptom. The expert maps each officer-scored clue — stepping off the line, raised arms, hopping — directly to the documented vestibular dysfunction.

Conditions that cause nystagmus and the HGN test. The horizontal gaze nystagmus test works on the theory that alcohol causes involuntary eye jerking at specific gaze angles — but plenty of things unrelated to alcohol cause nystagmus too: inner ear disorders, multiple sclerosis, certain medications like anti-seizure drugs and sedatives, head trauma, or naturally occurring congenital nystagmus. Someone who tested positive on the HGN because of an underlying condition wasn't showing alcohol-induced eye movement at all. The expert documents the specific nystagmus pattern in the medical records and compares it to what the officer recorded, showing it matches the condition, not alcohol.

Movement disorders and coordination tests. Conditions affecting motor control and gait — multiple sclerosis, Parkinson's disease, peripheral neuropathy, among others — directly affect the walk-and-turn and one-leg stand tests. Someone whose gait was unsteady, who couldn't walk heel-to-toe, or couldn't balance on one leg because of a movement disorder wasn't failing those tests because of alcohol — they were showing the motor symptoms of their actual condition.

Medications: When a Prescribed Drug's Side Effects Look Like Intoxication

Plenty of prescription and over-the-counter medications produce symptoms mistakable for alcohol impairment — drowsiness, slurred speech, slowed reflexes, unsteady gait, trouble concentrating. This defense looks at whether the medication was lawfully prescribed, whether it was being taken as directed, whether the observed symptoms match the medication's known side effects rather than alcohol impairment, and whether any blood or urine test showed a therapeutic level rather than an abuse level.

Fatigue and Illness: Ordinary Symptoms Officers Still Attribute to Alcohol

Extreme fatigue, viral illness, fever, and allergies all produce symptoms — red or watery eyes, slurred speech, slowed movement, trouble concentrating — that officers commonly associate with alcohol. Someone who'd been awake 24 hours, was fighting a significant illness, or dealing with severe allergies can present symptoms that are entirely explainable without alcohol ever being involved.

HOW TITLE 17 AND RISING BAC COMBINE WITH MEDICAL DEFENSES

Medical condition defenses often work best paired with Title 17 violations and the rising blood alcohol defense, since the combination hits the prosecution's evidence from multiple independent angles at once.

GERD paired with the observation period. Where a reflux event happened during the observation period and the officer didn't address it, the GERD contamination defense and the Title 17 violation both attack the same breath test result — and they're stronger together than apart.

Ketosis paired with rising BAC. Where a defendant in ketosis also had a BAC that was still climbing at the time of testing, the expert can show the tested result reflects both a rising curve and ketone interference at once — making it doubly unreliable as a measure of the driving-time BAC.

Diabetes paired with Title 17. Where ketone interference and a deficient observation period both affected the same test, the combined challenge establishes the result was procedurally defective and scientifically unreliable at the same time.

WHY THIS DEFENSE CARRIES EXTRA WEIGHT FOR NON-U.S. CITIZENS

For a non-U.S. citizen, a medical condition defense that produces acquittal or dismissal is about the best immigration outcome available in a DUI prosecution, since no conviction and no plea means no immigration consequence to worry about at all.

How DUI Convictions Affect Non-U.S. Citizens

A standard first-offense DUI conviction doesn't automatically trigger immigration consequences in every case, but specific DUI-related charges and pleas can still qualify as crimes of moral turpitude under 8 U.S.C. § 1182(a)(2)(A)(i)(I), triggering inadmissibility or deportability depending on the specific facts. Acquittal or dismissal through the medical condition defense removes that uncertainty completely.

Before Any Non-Citizen Defendant Enters a Plea:

• Check whether a plea to the DUI offense, or any lesser or related offense, would count as a crime of moral turpitude under 8 U.S.C. § 1182(a)(2)(A)(i)(I) or affect any pending or expected immigration proceeding — before any plea is entered
• Treat every medical condition defense as an immigration priority, since acquittal or dismissal based on the medical evidence beats any reduced plea — even a wet reckless reduction carries immigration uncertainty that a full acquittal or dismissal eliminates entirely
• Obtain medical records immediately — treating physician records, pharmacy records, and any relevant lab results — since the earlier the expert has these in hand, the more complete and persuasive the defense becomes
• Don't let any DUI plea go forward without a full medical condition analysis and an honest read on whether the defense is achievable given the facts and the expert support available

This analysis starts at the first consultation in every DUI case involving a non-U.S. citizen.

TURNING A MEDICAL RECORD INTO A DEFENSE STRATEGY

Every DUI case gets David Chesley's direct attention — immediate medical history documentation, record gathering, retaining the right forensic toxicology or medical expert, and coordinating with any Title 17 or rising-BAC defenses that apply at the same time. Coverage spans every California county, available around the clock. No case gets handed to a junior associate.

What starts happening right away:

Medical history documentation — the defendant's full relevant history gets documented from their own account on day one, when it's most accurate.

Expert retention — a qualified forensic toxicologist or medical expert gets brought on to analyze exactly how the specific condition affected the specific evidence: field sobriety tests, the breath test result, and the officer's observations.

Medical records collection — treating physician records, pharmacy records, and lab results get pulled to document the diagnosis and its status on the date of the arrest.

Device-specific analysis — in ketosis and GERD cases, the specific breath testing device gets checked for its known susceptibility to ketone interference and mouth alcohol contamination.

Combined defense assessment — Title 17 violations and the rising-BAC defense get evaluated alongside the medical defense, pursuing the strongest combination together.

Immigration analysis — every available resolution gets checked for immigration consequences from the first consultation, with acquittal and dismissal pursued as the most protective outcomes.

Free, confidential case review — available 24/7, no obligation.
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YOUR MEDICAL HISTORY IS PART OF YOUR DEFENSE — USE IT

The prosecution must prove impairment — not merely that the defendant had symptoms that looked like impairment. Common resolutions through medical condition defenses:

• Hypoglycemia — impairment charge dismissed — medical records and expert testimony established defendant was experiencing a documented hypoglycemic episode; every symptom the officer attributed to alcohol was consistent with low blood sugar; VC § 23152(a) impairment charge not proven
• GERD — per se charge dismissed — documented GERD diagnosis and significant difference between two breath test results; forensic toxicologist explained mouth alcohol contamination mechanism; VC § 23152(b) per se charge dismissed
• Ketosis — reduced to wet reckless — defendant following ketogenic diet with physician documentation; expert established ketone compounds contributed to elevated breath test reading; prosecution unable to establish reliable BAC; reduced to VC § 23103.5
• Neurological condition — acquittal — vestibular disorder documented; expert specifically mapped each officer-scored field sobriety test clue to the vestibular dysfunction; field sobriety test evidence entirely undermined; acquitted
• Medication defense — acquitted — lawfully prescribed antihistamine with documented sedating side effects; expert established observed drowsiness and slowed reflexes consistent with therapeutic medication dose rather than alcohol impairment; acquitted on VC § 23152(a)
• GERD combined with Title 17 violation — documented GERD diagnosis combined with 11-minute observation period established from timestamps; mouth alcohol contamination mechanism and procedural violation presented together; breath test result excluded; DUI charge dismissed
• Fatigue and illness — defendant had been awake for 28 hours; physician documented significant viral illness; expert established observed symptoms consistent with extreme fatigue and illness rather than alcohol impairment; acquitted
• Immigration-safe resolution — non-U.S. citizen; combined GERD and ketosis defense developed with forensic toxicologist expert; expert established multiple medical explanations for both officer observations and elevated breath test result; DUI charge dismissed without any plea; immigration consequences avoided

WHY CLIENTS WITH A MEDICAL EXPLANATION CALL THIS OFFICE

Direct, personal attention — statewide, 24/7.
David Chesley personally handles medical condition DUI defenses across every California county — Los Angeles, San Diego, Orange County, San Francisco, Sacramento, Fresno, San Jose, Riverside, San Bernardino, Ventura, and every other jurisdiction. Available around the clock, because these defenses need immediate documentation of medical history and records while they're most complete and accurate.

Straight talk, always.
Medical condition defenses range from situations where the condition fully explains the prosecution's evidence and the charge should be dismissed, to cases where it explains some of the evidence and creates real reasonable doubt, to cases where the condition's effect is limited and other defenses have to carry the case. You deserve an honest read on which one applies here — no false promises, no sugarcoating.

The defense most defendants with medical conditions never know to raise.
Plenty of people with diabetes, GERD, ketosis, inner ear disorders, and similar conditions accept pleas without anyone ever explaining that their own medical condition might explain the officer's observations, the field sobriety results, or the breath test reading itself. This analysis happens in every DUI case from the first consultation.

Flexible payment plans are available, because cost shouldn't decide whether someone facing a DUI charge — where a medical condition may have caused or contributed to the evidence — gets experienced representation.

FREQUENTLY ASKED QUESTIONS

Can a medical condition really defeat a DUI charge?
Yes — and it's one of the most powerful, most underused defenses available. A DUI charge requires proof of alcohol impairment or a BAC at or above 0.08%. When a medical condition produces symptoms mimicking impairment, throws off field sobriety test performance, or causes false or elevated breath test readings, the prosecution's evidence proves the medical condition, not alcohol impairment. This gets built from medical records, the defendant's history, and expert testimony from a forensic toxicologist or medical expert.

How does GERD or acid reflux affect a breath test?
GERD and acid reflux push stomach contents — including any alcohol present — back up into the esophagus and mouth. If that happens during or right before testing, the device measures contaminating mouth alcohol along with the deep-lung air it's supposed to measure, producing a reading well above the actual BAC. The two breath results get checked for differences consistent with that contamination, and a forensic toxicologist explains the mechanism to the jury.

Can a keto diet or fasting cause a false breath test reading?
Yes, in some circumstances. Ketosis produces acetone and isopropanol, which some devices can misread as ethanol. How much of a problem this is depends on the specific device and the defendant's ketone level — the device's known susceptibility gets analyzed, and the expert connects the dietary state to that device's specific measurement quirks.

How does diabetes affect DUI evidence?
In multiple ways at once. Hypoglycemia produces symptoms nearly indistinguishable from intoxication — slurred speech, confusion, unsteady gait. Hyperglycemia and ketosis produce acetone, which creates fruity breath easily mistaken for alcohol and can inflate breath test readings. Either condition alone can produce every symptom an officer reads as alcohol impairment, without any alcohol being involved.

Do neurological conditions affect field sobriety tests?
Significantly, yes. Inner ear disorders affect balance tests directly. Conditions that cause nystagmus produce positive HGN results regardless of alcohol. Movement disorders affect the walk-and-turn and one-leg stand. Any condition touching the specific function a test measures can produce the exact signs an officer scores as impairment, with no alcohol involved.

Are payment plans available?
Yes — the Law Offices of David Chesley offers flexible payment plans, because cost shouldn't decide whether someone facing a DUI charge, where a medical condition may be behind the evidence, gets experienced representation. These options get discussed during the free consultation.

Still have questions? We're available 24/7 for a free, no-obligation consultation. 📞 (800) 755-5174

DISCUSS YOUR MEDICAL HISTORY — FREE, CONFIDENTIAL CONSULTATION

Medical condition DUI defenses are among the more time-sensitive defenses available, since the evidence behind them is most complete right after the arrest. The defendant's own recollection of exactly what they were experiencing — the hypoglycemic confusion, the reflux event, the balance trouble from an inner ear condition — loses precision fast, and that precision is what a medical expert needs to connect the condition to the specific evidence. The relevant medical records — physician documentation, endocrinologist notes, neurology records — need requesting early too, since the sooner an expert has them, the more complete the analysis. And the specific breath testing device deserves its own look, since its particular susceptibility to ketone interference or mouth alcohol contamination is often the most technically powerful piece of the defense. For non-U.S. citizen defendants, the same urgency applies to the immigration analysis under 8 U.S.C. § 1182(a)(2)(A)(i)(I) — a medical defense that produces acquittal or dismissal is the cleanest way to eliminate that uncertainty, but only if it gets developed early.

Don't accept a DUI conviction before your medical conditions have been checked against every piece of the prosecution's evidence. Don't assume the symptoms the officer observed were alcohol-related when a medical condition may explain all of them. Don't assume the breath test reading is accurate when GERD, ketosis, or diabetes could have affected it. And don't wait to make the call. If you've been charged with DUI in California and have a medical condition that may have affected the evidence, reach out now.

The Law Offices of David Chesley offer a free, confidential consultation available 24 hours a day, 7 days a week. No judgment. No pressure. Honest assessment of your medical conditions and their impact on the evidence — and what expert analysis would establish if they apply.

Flexible payment plans available — because cost should never be the reason someone charged with DUI — when their medical condition explains the evidence against them — goes without the experienced defense this case demands.

David Chesley handles medical condition DUI defenses in criminal courts across all of California — Los Angeles County, Orange County, San Diego County, Riverside County, San Bernardino County, Ventura County, Santa Barbara County, Kern County, Fresno County, Sacramento County, Alameda County, Santa Clara County, San Francisco County, Contra Costa County, San Joaquin County, Stanislaus County, Monterey County, and every other jurisdiction statewide.

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"A DUI requires proof of alcohol impairment or legal BAC at the time of driving. Diabetes, GERD, ketosis, neurological conditions, medications, and other medical issues can produce every symptom and test result the prosecution relies on without any alcohol. My commitment is documenting your medical history, retaining the right experts, and presenting the defense — often combined with Title 17 or rising BAC — to show the evidence proves a medical condition, not impairment."
— David Chesley, California Criminal Defense Attorney