The ‘Controlled Herb’ Framework Explained

Cannabis flower in Thailand is a “controlled herb” (สมุนไพรควบคุม), not a narcotic. Since 26 June 2025 it has been governed under the Protection and Promotion of Thai Traditional Medicine Knowledge Act B.E. 2542 (1999), administered by the Department of Thai Traditional and Alternative Medicine. This single classification decision shapes almost everything about how cannabis is sold, prescribed, and penalised today. This guide explains what the classification actually is, why it is not the same as full legalisation, and the practical consequences for operators, patients, and consumers.

For the wider legal picture, start at our Thailand cannabis law hub.

The Short Answer

Thai law now treats cannabis on two separate tracks depending on the product:

• Cannabis flower is a controlled herb under the Traditional Medicine Act B.E. 2542. Lighter penalties, licensed through DTAM, prescription required to buy.
• Cannabis and hemp extracts above 0.2% THC remain Category 5 narcotics under the Narcotics Code. Stricter penalties, separate licensing.

Getting this split right is the foundation of compliance. Most costly mistakes come from treating the whole plant as one legal category when it is not.

What “Controlled Herb” Actually Means

A controlled herb is a plant that the Ministry of Public Health has formally designated for control under the Traditional Medicine Act. The designation gives the state authority to regulate who may grow, sell, possess, and export the plant, and under what conditions, without classifying it as a narcotic drug.

For cannabis, the mechanism was a Ministry of Public Health notification designating cannabis flower a controlled herb, effective 26 June 2025. Licensing to sell, possess, or export controlled cannabis flower runs under the sale and related provisions of the Traditional Medicine Act, with mandatory reporting to DTAM through forms Phor.Tor.27, 28, and 29 (covering source, usage, and inventory).

Note the historical point that matters for classification: cannabis flower has not been returned to the Category 5 narcotics list. The 2022 decriminalisation removed it from that list, and the June 2025 change re-restricted it through the traditional-medicine route instead of re-listing it as a narcotic. That choice is deliberate and it is what keeps flower on the lighter track.

Traditional Medicine Act vs the Narcotics Code

The two statutes are the heart of the framework. This table sets out how they differ for cannabis.

The dividing line between the two tracks is the 0.2% THC threshold. At or below 0.2% THC, a product generally falls under food, cosmetic, or herbal-product regimes. Above 0.2% THC, an extract is a Category 5 narcotic and is governed by a separate extract regulation, published 26 March 2026 and effective 26 April 2026, which limits extracts to four permitted purposes: medical, research, industrial, and official narcotics-suppression activities.

What the Classification Does Not Mean

The controlled herb route is often described loosely as “cannabis is legal in Thailand.” That is misleading. The classification does the following things and no more:

• It legalises cannabis flower only within a medical and traditional-medicine framework.
• It requires a licence to sell and a PT 33 prescription to buy. See our PT 33 prescription guide for how prescriptions work in practice.
• It bans recreational sale and advertising.
• It carries lighter penalties than the narcotics track, but it still criminalises unlicensed sale, sale without a prescription, and public-nuisance use.

In other words, the classification is a controlled legal channel, not an open market. Operating outside the channel is still an offence.

Practical Consequences

For businesses

If you sell cannabis flower, you are a controlled-herb licensee under DTAM, not a general retailer. That means a licence, a qualifying practitioner on-site, prescription-only sales, DTAM reporting, and facility standards. If you handle extracts above 0.2% THC, you are in the narcotics regime and need a separate Category 5 licence entirely. Many operators need to understand both tracks. See our business and compliance guidance for the operational detail.

For patients and consumers

You can access cannabis flower legally, but only with a PT 33 prescription from a licensed clinic, and only for purchase from a licensed outlet. CBD and hemp products below 0.2% THC do not require a prescription because they fall outside both the controlled-herb-flower rules and the narcotics track.

For the penalty you face

Because two statutes apply, the penalty for a violation depends on which track the conduct falls under. Prescription-less sale of flower is penalised under the Traditional Medicine Act; handling high-THC extract without a Category 5 licence is a narcotics offence. Our penalties guide sets out the figures and the important distinction between the sale penalty and the separate public-smoking fine.

Why the Framework Is Temporary

The controlled-herb classification is a ministerial construct, not a standalone statute. It was created by notification and can be adjusted by notification. If Thailand’s draft Cannabis and Hemp Act passes, it is expected to supersede this framework with primary legislation. Track that bill through our Cannabis and Hemp Act tracker, because a change in the underlying framework would change how cannabis is classified and penalised.

Verification Note

The controlled-herb classification and the two-track split are well corroborated across primary reporting and law-firm analysis. The specific section numbers of the Traditional Medicine Act cited in secondary sources should be confirmed against the Thai text before relying on them in a legal filing. This page is general information, not legal advice. Confirm your specific situation with a qualified Thai legal professional.