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A lot of drivers assume Pennsylvania DUI law is mostly about alcohol, marijuana, prescription drugs, or other scheduled controlled substances. That assumption is no longer safe.
In Commonwealth v. Walsh, 2026 PA Super 47 (March 16, 2026), the Pennsylvania Superior Court held that a DUI case could move forward where the driver's blood test was negative for alcohol and negative for scheduled controlled substances. The only substances detected were kratom and caffeine.
The short answer
Yes. Under 75 Pa.C.S. § 3802(d)(2), Pennsylvania can pursue a DUI charge where the Commonwealth claims the driver was under the influence of a “drug or combination of drugs” to a degree that impaired safe driving. According to Walsh, that subsection is not limited to controlled substances.
That means kratom can support a DUI charge. So can caffeine, over-the-counter cold medicine, sleep aids, CBD, and other legal substances if the Commonwealth can prove they actually impaired the driver.
What happened in Walsh
The driver in Walsh was stopped in Delaware County after erratic driving. The officer reportedly observed signs such as constricted pupils, exaggerated reflexes, irritability, and difficulty speaking. The driver refused field sobriety tests. Officers also found several bottles of kratom in the vehicle, including opened containers and a liquid that appeared to be kratom.
A hospital blood draw came back positive for mitragynine, the active compound in kratom, and caffeine. Nothing else. The trial court dismissed the DUI charge after concluding kratom and caffeine were not controlled substances. The Commonwealth appealed, and the Superior Court reversed.
The statutory split
The case turned on two different phrases in the DUI statute
Section 3802(d)(1)
This subsection is written around controlled substances specifically.
It addresses driving with certain controlled substances in the blood.
The statutory word choice is narrow and schedule-based.
That is why lawyers often start there when they think about drug-related DUI charges.
Section 3802(d)(2)
This is the subsection the Superior Court said reaches further.
It prohibits driving while under the influence of a drug or combination of drugs to a degree that impairs safe driving.
The Superior Court treated the word drug as broader than controlled substance.
That broader wording is what allowed the kratom prosecution to move forward.
What the Superior Court held
The Superior Court focused on the legislature's choice to use two different terms in adjacent subsections: “controlled substance” in one place and “drug” in the next. The court concluded that difference was deliberate. If the General Assembly intended subsection (d)(2) to reach only controlled substances, it could have said so. It did not.
The court also looked to the Pennsylvania Controlled Substance, Drug, Device and Cosmetic Act, which defines a drug broadly as a substance, other than food, intended to affect the structure or function of the human body. Under that definition, kratom fit. So did caffeine.
The result is a straightforward but important rule: legality of the substance does not end the DUI analysis. The Commonwealth can still prosecute if it says the substance qualifies as a drug and impaired safe driving.
Why this matters at a traffic stop
The practical takeaway is bigger than kratom. A Pennsylvania DUI investigation can now lean on legal products that many drivers would never have guessed could support a DUI charge. A blood test that comes back clean for alcohol and clean for scheduled controlled substances may no longer end the case.
That also means “but it's legal” is not a complete defense. If the Commonwealth believes a legal supplement, medication, or stimulant affected safe driving, the case may keep moving.
What drivers should understand now
Walsh changed the practical risk picture
These are the real-world consequences of the case for Pennsylvania drivers.
Legal substances can support a DUI charge if the Commonwealth claims they impaired safe driving.
Negative alcohol and controlled-substance results do not automatically kill a DUI case anymore.
The fight in these cases often becomes more technical because causation and impairment are less obvious than in a standard alcohol case.
Early motion practice and issue preservation matter, especially if constitutional or statutory arguments may need to be raised.
Where defense arguments still live
Walsh resolved one statutory issue. It did not give prosecutors a blank check. The Commonwealth still has to prove that the substance actually caused impairment. That is not automatic, especially with something like kratom, caffeine, or another legal supplement where the effects are less familiar and more case-specific.
Officer qualifications also matter. An officer who has no training in identifying kratom-related impairment may not be well-positioned to draw that conclusion persuasively. And where the prosecution's evidence is thin, the defense can still challenge probable cause, stop validity, sufficiency of the observations, and whether expert testimony is needed to connect the blood result to the alleged driving behavior.
There is also a procedural lesson in the opinion. The trial judge discussed constitutional concerns, including vagueness and due process, but those issues were not preserved in a way that allowed the Superior Court to reach them. That is a reminder that these arguments often have to be raised early if the defense wants to keep them alive.
Early defense sequence
How these nontraditional DUI cases usually need to be handled
The common mistake is assuming the case will collapse because the substance is legal. After Walsh, that is not enough.
Step 1
Preserve the stop and testing facts
Lock down the timeline, paperwork, blood-test information, and what the officer actually observed before the case gets reduced to a thin report narrative.
Step 2
Test the causation theory
The Commonwealth still has to connect the substance to the alleged impairment. That may require more than a lab result and a conclusory opinion.
Step 3
Evaluate officer training and proof quality
If the officer cannot explain what kratom impairment looks like or how they know it, that can matter a lot.
Step 4
Preserve legal arguments early
Where statutory, constitutional, or suppression issues exist, they need to be raised before those arguments are lost.
What to do if this is your case
If you are facing DUI charges in Westmoreland, Allegheny, Indiana, or a nearby county and the substance at issue is kratom, caffeine, an over-the-counter medication, or another non-scheduled product, the worst move is to assume the charge will disappear by itself. After Walsh, it may not.
These cases still can be fought, but they usually have to be worked carefully and early. Leonard Law Group handles Pennsylvania DUI defense matters involving stop issues, testing questions, causation disputes, ARD strategy, and the local court process across Western Pennsylvania.
This article discusses a recent appellate decision for general informational purposes and is not legal advice. Reading it does not create an attorney-client relationship. Every case is fact-specific and outcomes can vary.
Practice area fit
This issue often belongs in DUI Defense for Drug and Impairment Cases.
Cases involving kratom, prescription medication, legal supplements, or other alleged drug impairment still belong in the firm’s DUI defense practice, especially where the Commonwealth’s proof of causation and impairment needs to be tested carefully.
Next step
Charged with DUI after kratom, caffeine, or another legal substance?
After Walsh, these cases do not just disappear because the blood test is negative for alcohol and scheduled drugs. The practical question is whether the Commonwealth can actually prove impairment and causation well enough to win.
Related reading
Readers with this problem often review these next.
What Happens if You Refuse a Breath Test in Pennsylvania?
A breath-test refusal can trigger a license suspension and reshape a DUI case quickly, even before the court date arrives.
Read articleWhat Happens to a DUI Case in Westmoreland County After the Preliminary Hearing?
A DUI arrest in Latrobe, Murrysville, Hempfield, or another local municipality does not necessarily stay there. Once charges are held for court, the case usually shifts toward the Westmoreland County Court of Common Pleas in Greensburg.
Read articleYour Rights During a Traffic Stop in Pennsylvania
A traffic stop can get worse fast if you do not know what you have to provide, what you can refuse, and when to stop talking.
Read articleWhy clients call Leonard Law Group
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This article is for general information only and is not legal advice. Every case depends on its specific facts.