In Thailand, cannabis flower is a “controlled herb” under traditional-medicine law. Cannabis and hemp extracts above 0.2% THC are a “Category 5 narcotic” under the narcotics law. The two categories have separate licences, separate rules on who may hold them and separate penalties. If you grow, process, prescribe or sell, the THC result on a lab certificate tells you which law covers your product.
Two categories under two different laws
Thai law sorts cannabis products by what they are and how much THC they contain. THC (tetrahydrocannabinol) is the main intoxicating compound in cannabis.
| Controlled herb (สมุนไพรควบคุม) | Category 5 narcotic (ยาเสพติดให้โทษประเภท 5) | |
|---|---|---|
| What it covers | Cannabis flower (ช่อดอกกัญชา) | Cannabis and hemp extracts above 0.2% THC |
| Parent law | Protection and Promotion of Thai Traditional Medicine Knowledge Act B.E. 2542 (1999) | Narcotics Code B.E. 2564 (2021) |
| Main rules now | MoPH Notification on Controlled Herbs (Cannabis) B.E. 2568, in force 26 June 2025; Ministerial Regulation on Controlled Herbs (No. 2) B.E. 2569, in force 30 April 2026 | Ministerial Regulation on Cannabis or Hemp Extracts B.E. 2569, in force 26 April 2026 |
| Who may hold a licence | Licence criteria for flower were tightened in April 2026 | Only Thai juristic persons that are not “foreign” under the Foreign Business Act B.E. 2542, state agencies and the Thai Red Cross Society |
| Supply to patients | Only with a PT 33 (ภ.ท.33) prescription, for at most 30 days | Only for the purposes the extract regulation allows |
| Advertising and online sale | Prohibited for flower | Set by the narcotics law. Ask the licensing office before you promote or sell any extract |
To convert a Thai year (B.E.) to the Western year, subtract 543. B.E. 2569 is 2026.
What to do: Write down every cannabis product you handle and put it in one column of this table. That tells you which law and which licence apply to it.
Where the old 1979 Narcotics Act fits
For decades, cannabis was a Category 5 narcotic under the Narcotics Act B.E. 2522 (1979). The Narcotics Code B.E. 2564 (2021) replaced that Act. It kept the system of five numbered categories.
In 2022, the plant was taken off the Category 5 list, but extracts above 0.2% THC stayed on it. Flower later became a controlled herb. The full history is in Thailand’s Cannabis Rules, 2022 to 2026.
Old articles and seed listings often still quote the 1979 Act. If a post says “cannabis is Category 5,” check its date before you trust it.
The 0.2% line for extracts
An extract is a product made by pulling cannabinoids out of the plant, for example an oil. If THC is above 0.2% by weight of the extract, the product is a Category 5 narcotic. To produce, import, export, sell or possess it, you need a licence under the Narcotics Code.
Individuals cannot hold this licence. So a home grower who makes a high-THC oil may be handling a Category 5 narcotic without a licence. Published sources do not yet confirm whether rosin, hash or home-made oil counts as an “extract” under this regulation.
An extract at or below 0.2% THC, such as many hemp CBD oils, can fall outside Category 5. The exemption has conditions, so check them before you import or sell. Other product rules may still apply, for example food, cosmetic or herbal-product rules.
What to do: Before you make, keep or sell any concentrate, ask the licensing office in writing whether it counts as an “extract.” Their answer tells you whether you need a Category 5 licence.
The 1.0% figure: the hemp line, not a narcotic line
You will also see “1.0% THC in dried plant.” That figure belongs to the definition of hemp (กัญชง). It came from Thailand’s earlier hemp rules, made when hemp was still a Category 5 narcotic. It set THC in dried leaves and flowers at no more than 1.0% of dry weight. It decided whether a plant counted as hemp or high-THC cannabis. It did not decide whether a plant was a narcotic.
Since 2022, plant parts are not on the Category 5 list. High-THC flower is controlled through the controlled-herb rules instead. Hemp vs High-THC Cannabis explains the hemp line in detail.
In short, 0.2% applies to extracts and decides narcotic or not. 1.0% comes from the hemp definition for dried plant material and separates hemp from cannabis.
How a sample is tested
A lab measures THC as a percentage of the sample’s weight (% w/w). Most labs use liquid chromatography (HPLC). This method measures THC and THCA separately. THCA is the acid form that raw plants make. It turns into THC when heated.
Many labs also report “total THC,” which is THC + 0.877 × THCA. This figure matters a lot for raw, unheated extracts. They can show low THC but high THCA. Published summaries of the rules say “THC by weight” and require a THC test for every production batch. They do not say whether this means THC alone or total THC, or which test method to use. Ask the licensing office which figure and method it accepts.
Dried plant results are given on a dry-weight basis, so the lab corrects for moisture. In Thailand’s rainy season, flower can take up water from the air. Ask the lab whether it reports dry weight or “as received.”
Every result has a measurement uncertainty, for example 0.19% ± 0.03%. A result just under 0.2% can come out above it on a retest. Choose a lab accredited to ISO/IEC 17025, the international standard for testing labs, and ask the licensing office which labs it accepts. To read the report itself, see How to Read a Cannabis Certificate of Analysis.
What to do: For each extract batch, keep a certificate that shows THC, THCA and total THC, together with the uncertainty. If the upper end of the range reaches 0.2%, treat the batch as Category 5 until the authorities confirm otherwise.
Why the line matters
The penalty under Section 78 of the 1999 Act is up to 1 year in prison and/or a fine of up to 20,000 baht. It covers unlicensed sale, export, processing or research of a controlled herb. It does not cover extracts. Category 5 offences fall under the Narcotics Code, which has its own, separate penalties.
Extract licences issued under the earlier rules stay valid only until 31 December 2026. The draft Cannabis Control Act is not law yet. The Cabinet approved it on 22 September 2026 and sent it to the House. The two April 2026 regulations, including the four conditions for flower licences, are explained in Thailand’s Two Ministerial Regulations of B.E. 2569.
Steps you can take this week
- Mark each product as flower, plant material or extract. This tells you whether the controlled-herb rules or the narcotics law apply.
- Get a lab certificate for every extract batch, showing THC, THCA, total THC and uncertainty. This shows which side of 0.2% the batch is on.
- Ask the lab whether its method matches what the licensing office requires. A result in the wrong format may not be accepted at an inspection.
- If you have foreign shareholders and handle extracts, ask a Thai lawyer to check your share register against the Foreign Business Act before 31 December 2026. The answer tells you whether you can keep your licence.
- For flower, check that every sale has a matching PT 33 prescription. This is the rule inspectors check first.
This is general information, not legal advice. Check the Thai text in the Royal Gazette, the official journal where laws are published.
If you have had a THC test questioned, or asked an office whether a product counts as an extract, please post what they told you below this topic. Questions are welcome too.
References
- Protection and Promotion of Thai Traditional Medicine Knowledge Act B.E. 2542 (1999)
- Narcotics Code B.E. 2564 (2021)
- Notification of the Ministry of Public Health Re: Controlled Herbs (Cannabis) B.E. 2568 (2025)
- Ministerial Regulation on Cannabis or Hemp Extracts (Category 5 Narcotics) B.E. 2569 (2026)
- Ministerial Regulation on Controlled Herbs (No. 2) B.E. 2569 (2026)