CBD, delta-8, other hemp-derived products, and kratom are all within reach of Montana's DUI law if they impair your driving, and a hemp product that puts THC in your blood is treated like any other source of THC. None of them has a special exemption. This is also an area where product rules are shifting at the federal level, so this page separates what the DUI statute says, which is stable, from what is still moving. It is part of our Montana DUI Guide.
The DUI Statute Looks at Effect, Not Legality
Montana's impairment offense applies to a person under the influence of "alcohol, any drug, or a combination of alcohol and any drug" (MCA § 61-8-1002(1)(a)). A drug is "any substance that when taken into the human body can impair a person's ability to operate a vehicle safely" (MCA § 61-8-1001(7)).
Nothing in that definition depends on whether a product is sold legally, labeled as a supplement, or derived from hemp. If the State can prove a substance diminished your ability to drive safely, the impairment offense applies.
| Product | Per se limit | Impairment charge possible? | Note |
|---|---|---|---|
| CBD products | No limit for CBD itself | Only if the product actually impaired you | A hemp product may contain some THC, and the THC limit has no exception for its source. |
| Delta-8 and other hemp-derived THC products | The statute says "tetrahydrocannabinol" and does not say delta-9 | Yes, if it diminished your ability to drive | How a laboratory reports delta-8, and whether it supports a per se charge, is not answered in the text. |
| Kratom (mitragynine) | None | Yes, if it diminished your ability to drive | A blood test finds it only if the laboratory looks for it. |
THC From a Hemp Product Is Still THC
The per se marijuana offense applies when a person's "tetrahydrocannabinol level, excluding inactive metabolites, as shown by analysis of the person's blood or other bodily substance, is 5 ng/ml or more" (MCA § 61-8-1002(1)(d)). For a driver under 21 the offense is any amount (MCA § 61-8-1002(1)(e)(ii)).
The statute measures what is in the blood. It does not ask whether the THC came from a dispensary product, a hemp-derived beverage, or a CBD oil. Montana's hemp definition allows a total delta-9 THC concentration of not more than 0.3 percent on a dry weight basis (MCA § 80-18-101(1)), so a lawful hemp product is not necessarily a THC-free product. How much THC a given product delivers depends on the product and the amount used, and we are not aware of a reliable way for a consumer to predict a blood level from a label.
For drivers under 21, the any-amount rule makes this a real exposure. See our under-21 DUI page.
CBD
There is no CBD limit in Montana's DUI statute, and CBD is not on the per se drug list. NHTSA's Drugs and Human Performance Fact Sheets: 2024mention CBD mainly as a marker. They note that CBD "cannot be used as a marker of recent cannabis use because there are many high-concentration CBD-only products on the market."
In a DUI case, then, a CBD finding by itself proves little. The questions are whether THC was also present, at what level, and whether there is any evidence of impairment.
Delta-8 and Other Hemp-Derived THC Products
Delta-8 THC is a form of tetrahydrocannabinol. NHTSA's fact sheets list it among cannabinoids that act as partial agonists at the body's cannabinoid receptors. Two points follow for a Montana driver.
First, a product that produces a marijuana-like effect can support an impairment charge like any other drug.
Second, the per se subsection uses the general word "tetrahydrocannabinol." It does not say delta-9, and it does not define the term. Whether a laboratory result for delta-8 alone can prove the per se offense is a question the text leaves open. It would turn on what the laboratory's method measures and how the result is reported, which is a matter for the toxicology report and, if needed, an independent toxicologist.
On the product side, Montana's marijuana chapter does not permit the "production, delivery, distribution, purchase, or consumption of synthetic cannabinoid products" (MCA § 16-12-108(1)(d)), and both the marijuana and hemp definitions exclude synthetic cannabinoids. Whether a particular delta-8 product falls in that category is a regulatory question this page does not try to answer.
Kratom
Kratom is a plant product whose main active alkaloid is mitragynine. NHTSA's 2024 fact sheets include a mitragynine entry. They report that:
- its effects are dose dependent, stimulant at lower doses and depressant at higher doses;
- for drug recognition purposes it is categorized as a narcotic analgesic;
- effects have been described as strongest 2 to 4 hours after ingestion and lasting 5 to 7 hours;
- published impaired driving case reports describe swerving, poor balance, and tremors in drivers whose blood contained mitragynine, in each case together with at least one other drug;
- as of that publication, kratom was not federally scheduled but was controlled in several states.
Montana's per se list in MCA § 61-8-1002(1)(f) does not include mitragynine. A kratom DUI would have to be an impairment case, and the usual rule applies: a positive test does not in itself prove a person was under the influence, and other competent evidence is required (MCA § 61-8-1018(1)(a)).
State regulation of kratom has been under discussion in Montana ahead of the 2027 legislative session. Check current law before relying on anything you read about its legal status, including here.
Federal Hemp Rules Are Changing in Late 2026
Congress rewrote the federal definition of hemp in late 2025, with a delayed start. As the law stood when this page was reviewed, the change arrives in two steps: part of it on November 12, 2026, and the rest, including the provisions aimed at intoxicating hemp-derived THC products, on December 11, 2026. Congress has already postponed part of the change once, and further bills are pending. We are not stating the federal rules as settled.
For a DUI case the federal schedule matters less than it seems. Montana's DUI statute does not refer to federal hemp law. Whether a product was lawful to sell on the day you bought it does not decide whether you were under the influence or what was in your blood.
If One of These Products Is Part of Your Case
- Keep the product, its packaging, and the receipt. The label and any certificate of analysis may matter.
- Write down what you used, how much, and when.
- Get the full laboratory report and see exactly which compounds were measured.
- Do not assume a "hemp" or "THC-free" label will be accepted as an explanation. The statute has no such exception.
How THC results are interpreted is covered in our guide to how long THC stays in your blood and on our THC DUI page.
This page explains Montana DUI law in general as of the 2025 Montana Code Annotated. Product regulation at the state and federal level is changing and is not covered in full here. It is not legal or medical advice about your specific case.