Thai food had cannabis leaf in it long before anyone in Bangkok opened a dispensary, and the legal position on cannabis in food is quite different from the legal position on cannabis flower. Both facts get lost in coverage that treats “cannabis in Thailand” as a single subject.
This post covers the culinary tradition, the crucial distinction between leaf and flower in the kitchen, and what the law actually permits in a commercial food business. It assumes you have read topic 1316 (Edibles and Decarboxylation), and does not repeat the dosing and safety material there — because, as you will see, most of that material does not apply to the traditional use.
Leaf and flower are different ingredients, legally and chemically
Start here, because everything else follows.
Cannabis leaf is a vegetable. Fresh leaves contain cannabinoids overwhelmingly in their acid forms — THCA rather than THC. THCA is not intoxicating. Converting it requires decarboxylation: sustained heat, conventionally described as around 110–120°C for a period of time, and critically it requires that heat to reach the compound.
This is the pharmacological explanation for something that puzzles visitors: Thai cooks have used cannabis leaf in food for generations without producing intoxicated diners. Two things work together:
- The amounts are small. Fan and sugar leaves carry far less cannabinoid than flower. Figures of around 1% or less are commonly reported, though this varies by plant. A herb quantity of leaf therefore contains little to begin with.
- A water-based method at about 100°C activates and extracts very little. A leaf dropped into a simmering pot of soup for twenty minutes is not efficiently decarboxylating: water boils at 100°C and holds the food there. THC is also not water-soluble, so even what does convert has limited opportunity to transfer into a broth without fat.
Low content combined with a poor activation and extraction method is what makes the leaf usable as a herb.
Cannabis flower is the opposite case in every respect. It carries far higher cannabinoid content, and the standard culinary preparations for it — infusing into oil or butter over sustained heat — are specifically designed to decarboxylate and to extract into fat. That is a drug preparation, and it should be treated as one.
Even once THC is swallowed, it behaves very differently from smoked cannabis. Oral bioavailability is roughly 4–12% (about 6% on average in the classic cookie study, and higher in some oil formulations). Effects typically begin 30–90 minutes after eating (Grotenhermen, Clinical Pharmacokinetics, 2003). That delay is why people overdo edibles: they get impatient and take more.
The traditional use
Cannabis leaf appears in Thai cooking as an aromatic herb, in the same conceptual slot as holy basil, kaffir lime leaf or galangal, and it is often described as a tenderiser as well. We could not find a source that tests the tenderising claim. The leaf is most associated with the North and Northeast and with noodle soups in particular, and boat noodles are often described as the classic example.
The functional claims made for it in traditional cooking are about flavour depth and umami rather than about effect. Whether cannabis leaf contributes measurable umami compounds is not something we could source a study on, and we are not going to assert it. What is not in dispute is that the tradition treats it as a seasoning.
Culinary practice, as it is described:
- Fresh young leaves, torn or chopped, added towards the end of cooking, as with any soft herb
- One or two leaves per dish is the official guidance, which is smaller than some folk figures that circulate. The Department of Health (Ministry of Public Health) advised food businesses in 2022 to use 1 fresh leaf per dish for soups, curries, stir-fries and drinks and 1–2 fresh leaves for fried dishes. It also advised that consumers have no more than 2 cannabis-leaf dishes or drinks per day. This is a herb quantity, not an ingredient quantity.
- Sometimes fried as a garnish, or blanched and used in salads
- In broths, added to the simmering stock
The flavour is described as green and slightly bitter, closer to a bitter leafy green than to anything aromatic. It is not a strong flavour and it is not meant to be the point of the dish.
What the law actually permits
This is the part most sources get wrong, usually by conflating the food rules with the flower rules.
Under the Thai food framework, governed by Ministry of Public Health notifications under the Food Act:
Permitted as food ingredients:
- Parts of cannabis, except inflorescence and seeds
- Parts of hemp, except inflorescence
- Hemp seeds, hemp seed oil, hemp seed protein
- CBD extracts
with the requirement that they originate from domestically grown plants.
Prohibited:
- Inflorescence of cannabis and hemp in any food product. This is the flat prohibition and it is the one that matters most.
- Cannabis seeds and cannabis seed oil in any food product — note the asymmetry with hemp, where seeds are permitted
- Cannabis or hemp in infant formula, follow-on formula, complementary foods for young children, and energy drinks
Limits for packaged food. The product standard is MOPH Notification No. 427 B.E. 2564 (2021), Food Products Containing Parts of Cannabis or Hemp, as amended by Notification No. 438 B.E. 2565 (2022). As reported when the 2022 rules took effect, packaged food products may contain no more than 1.6 mg THC and 1.41 mg CBD per package. Seasonings have percentage limits instead: THC no more than 0.0032% and CBD no more than 0.0028% by weight. THC and CBD content must be stated on the label.
Restaurants and warning messages. Two 2022 instruments apply to food outlets:
- A Department of Health notification on using cannabis leaves in food establishments (No. 2, B.E. 2565). It sets out the leaf guidance quoted above.
- A Ministry of Public Health notification on cooked/ready-to-eat food sold at food outlets (No. 2, B.E. 2565), published in the Royal Gazette in late August 2022.
Together they require outlets to:
- show that they use cannabis or hemp
- list the dishes that contain it
- display safety advice: people under 20, pregnant and breastfeeding women, and anyone allergic should not eat these dishes; stop eating if symptoms appear; do not drive or operate machinery if drowsy
So the legal shape is clean and it matches the chemistry: cannabis leaf in a soup is a permitted food ingredient. Cannabis flower in a brownie is not a food product at all — it is a preparation of a controlled herb.
And the 2025 change made that harder, not easier. The Notification of the Ministry of Public Health Re: Controlled Herbs (Cannabis) B.E. 2568 was issued on 26 June 2025. Under it, ช่อดอกกัญชา, the flower, is a controlled herb:
- It may be dispensed only against a prescription on form ภ.ท. 33 (PT 33) from an authorised practitioner.
- Each prescription covers no more than 30 days and can be used once (no refills).
- Flower that is sold or exported must come from a GACP-certified cultivation site.
Sale of flower requires licensing. In 2026 two Ministerial Regulations B.E. 2569 tightened that licensing further: one for cannabis/hemp extracts (in force 26 April 2026) and the Ministerial Regulation on Controlled Herbs (No. 2) (in force 30 April 2026). The details of the second are covered in bai209. Neither changes the PT 33 prescription rules.
A restaurant cannot lawfully put controlled cannabis flower in a dish. The leaf is a separate question with a separate and more permissive answer.
Advertising. The 2568 notification prohibits advertising of controlled cannabis flower and prohibits online sale. Food advertising is now also governed by the Thai FDA’s Notification Re: Criteria for Food Advertising B.E. 2569, published in July 2026, which includes specific criteria for food containing cannabis or hemp. That applies to a restaurant promoting cannabis-leaf dishes, and bai248 covers it in detail. For the wider advertising and selling rules, see topic 1293 (Advertising and Selling Rules). Where exactly the boundary falls is one to check with a lawyer rather than to reason out from a forum post.
Practical guidance for a home cook
This applies to Thailand. In countries where cannabis is prohibited, possessing the leaf is illegal too.
Using leaf as a herb:
- Use fresh young leaves. Older leaves are tougher and more bitter.
- Add late, as with any soft herb. Prolonged boiling turns them grey and unpleasant.
- One leaf per dish (one or two for fried dishes) is the official guidance. There is no culinary reason to exceed it and it will taste worse if you do.
- Wash them. They were on a plant outdoors.
- Tell anyone you serve that the dish contains cannabis leaf.
- Be aware of one exception to the “no effect” rule: fat. If your dish is a rich coconut curry simmered for a long time, the conditions move somewhat towards extraction. This is not going to produce a strong effect from a herb quantity of leaf, but “no effect” is a statement about small amounts boiled in water, not a law of nature.
Flower is not a kitchen ingredient. In Thailand, cannabis flower is a controlled herb, available only on a PT 33 prescription for medical use, and inflorescence may not be used in food. For how oral cannabis products behave (decarboxylation, delayed onset, dosing), see topic 1316 (Edibles and Decarboxylation). In countries where cannabis is banned, including Vietnam and other Southeast Asian countries, making flower edibles is illegal.
For anyone running a food business
Six things, in order:
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Leaf, not flower. Inflorescence is prohibited in food, full stop.
-
Domestic sourcing. The food framework requires domestically grown material.
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Warning messages at outlets serving food containing cannabis, per the 2022 requirements.
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Not for children’s food products, and not in energy drinks.
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No cannabis seeds or cannabis seed oil — the permission for hemp seed does not extend to cannabis seed.
-
Check the current text before you build a menu. The cannabis framework in Thailand has changed repeatedly, and each change has made it stricter:
- the controlled-herb notification (June 2025)
- two Ministerial Regulations (April 2026)
- the new food-advertising criteria (July 2026)
A Cannabis Control Act is still only a draft: the Cabinet approved it on 22 September 2026 and sent it to the House. A rule that was accurate when this post was written may not be accurate when you read it. This is a matter for a Thai lawyer, not for a forum.
What we could not verify
- The THC/CBD package limits above come from press reports of the 2022 amendment. We did not check them against the Royal Gazette text of Notifications No. 427 and No. 438. We also could not confirm whether anything since 2025 has changed them.
- We could not confirm whether restaurants serving cannabis-leaf dishes require a specific registration beyond ordinary food-business licensing and the 2022 outlet rules.
- We found no analytical study of cannabinoid transfer from leaf into Thai broths, which is the study that would settle the “is it really inert” question quantitatively rather than mechanistically.
If a member has the Royal Gazette text of No. 427/No. 438 with the limits, please post it.
Sources:
- Tilleke & Gibbins, “Cannabis and Hemp Business Guide — Thailand”, 2025 edition: permitted and prohibited plant parts in food; Ministry of Public Health Notification No. 424.
- MOPH Notification No. 427 B.E. 2564, as amended by No. 438 B.E. 2565: limits as reported by NutraIngredients, 7 November 2022.
- Department of Health notification on using cannabis leaves in food establishments (No. 2) B.E. 2565: leaf guidance as reported by PPTV, MGR Online and Thairath, June 2022.
- MOPH notification on ready-to-eat food at food outlets (No. 2) B.E. 2565: as reported by The Standard, August 2022.
- Notification of the Ministry of Public Health Re: Controlled Herbs (Cannabis), B.E. 2568.
- JusLaws, “Ministerial Regulation on Controlled Herbs (No. 2) B.E. 2569”.
- Thai FDA, Notification Re: Criteria for Food Advertising B.E. 2569.
- Grotenhermen F., “Pharmacokinetics and pharmacodynamics of cannabinoids”, Clinical Pharmacokinetics 42:327–360 (2003).