The PT 33 (ภ.ท. 33) is the official Thai prescription form for cannabis flower. Since 26 June 2025, a business may sell flower to a member of the public only against this prescription, and one prescription covers at most 30 days. Clinics that prescribe, shops that dispense and farms that supply them all need to know three things: who may issue a PT 33, what it must record and what it does not allow.
What the PT 33 is
Cannabis flower (ช่อดอกกัญชา) is a controlled herb (สมุนไพรควบคุม). Its legal basis is the Notification of the Ministry of Public Health Re: Controlled Herbs (Cannabis), B.E. 2568. That Notification was issued under the Thai Traditional Medicine Protection Act B.E. 2542 (1999) and came into force on 26 June 2025.
Under the Notification, flower may be sold only with a PT 33 prescription. The form is titled “Prescription for Controlled Herb (Cannabis)” (ใบสั่งจ่ายสมุนไพรควบคุม (กัญชา)). You may see it written as ภ.ท. 33, พท.33, PT33 or “Phor Thor 33”. All of these names refer to the same form. The official form code is ภ.ท.33.
The Notification also bans advertising flower and selling it online. So for the public, the only lawful way to buy flower is in person, at a licensed seller, with a PT 33.
Who can issue a PT 33
Seven groups of licensed practitioners can write a PT 33. The prescriber must hold a valid licence in their own profession.
| Prescriber | Thai term | Licensing or certifying body (to verify the licence) |
|---|---|---|
| Medical doctor | แพทย์ | Medical Council of Thailand (แพทยสภา) |
| Thai traditional medicine practitioner | แพทย์แผนไทย | Thai Traditional Medicine Professional Council (สภาการแพทย์แผนไทย) |
| Applied Thai traditional medicine practitioner | แพทย์แผนไทยประยุกต์ | Thai Traditional Medicine Professional Council |
| Dentist | ทันตแพทย์ | Dental Council of Thailand (ทันตแพทยสภา) |
| Pharmacist | เภสัชกร | Pharmacy Council of Thailand (สภาเภสัชกรรม) |
| Traditional Chinese medicine practitioner | แพทย์แผนจีน | Healing Arts licence, Department of Health Service Support (กรมสนับสนุนบริการสุขภาพ) |
| Folk healer | หมอพื้นบ้าน | Ministry of Public Health (folk healer certificate) |
A licence to sell controlled herbs is not a licence to prescribe. A shop owner who is not in one of these seven groups cannot write a PT 33. To see which licence covers which activity, read Licensing and Compliance in Thailand.
What a PT 33 must record
Each item on the form has a purpose. Together they let the shop and an inspector check the sale.
- Patient identity. This shows who the flower is for.
- Diagnosed condition. This shows the medical reason for the prescription.
- Prescribed quantity. This sets the most the shop may dispense. The Notification sets no fixed amount. The prescriber decides the quantity based on treatment need.
- Number of days. The limit is 30 days for each prescription.
The diagnosis must also meet a clinical standard. It must fit the treatment guidelines and indications approved for the prescriber’s own profession. It must also be consistent with other medical documents that support the patient’s use.
How the process works
- The patient sees one of the seven prescribers. The prescriber assesses the patient and records a diagnosis that fits their profession’s guidelines.
- The prescriber fills in and signs the PT 33, with the quantity and the number of days (30 at most).
- The patient takes the PT 33 to a business licensed to sell controlled herbs.
- The shop checks the form, then dispenses no more than the written quantity.
- The shop keeps the prescription for one year. This lets an inspector match each sale to a prescription.
- When the days run out, the patient needs a new PT 33.
Forms that are signed in advance and left blank carry a serious compliance risk. The forum covers this in Blank-Signed PT 33 Prescriptions.
What a PT 33 covers, and what it does not
A PT 33 covers one thing: buying cannabis flower in Thailand from a licensed seller, in the quantity and for the days written on it.
It does not do the following:
- Licence you to grow, process or sell. Selling or processing a controlled herb without a licence (Section 46 of the 1999 Act) carries up to 1 year in prison and/or a fine of up to 20,000 baht (Section 78).
- Let you carry flower out of Thailand or possess it elsewhere. Visitors should read Travelling to Thailand for Medical Cannabis.
- Make flower an approved medicine. For the difference between prescribed flower and approved cannabinoid medicines, and for what the evidence supports, see Medical Cannabis: What the Term Means.
- Cover extract licensing. Extracts above 0.2% THC fall under a separate Ministerial Regulation on Cannabis or Hemp Extracts B.E. 2569, in force 26 April 2026. Licences for these extracts go only to Thai juristic persons that are not “foreign” under the Foreign Business Act, to state agencies and to the Thai Red Cross Society.
The rules may change again. The draft Cannabis Control Act is not law yet. The Cabinet approved the draft on 22 September 2026 and sent it to the House of Representatives.
Why it matters to growers, clinics and shops
Growers. GACP certification covers how you grow and handle the crop. It does not let you sell flower to the public. Flower reaches a patient only through a licensed seller and a PT 33. The Ministerial Regulation on Controlled Herbs (No. 2) B.E. 2569, in force 30 April 2026, made the licence criteria for flower stricter.
Clinics. Prescribe only for diagnoses within your profession’s approved guidelines. Keep the supporting medical documents.
Shops. A suspension can last up to 90 days per order (Section 52). After a revocation (Section 54), the business cannot get a new licence under the Act for two years. The same two-year ban applies to its directors, managers and other responsible persons (Clause 8(1)(e) of the 2016 licensing regulation). Under DTAM’s enforcement guidelines, selling flower without a PT 33 is a ground for suspension, and repeating the same breach can lead to revocation.
What you can do now
- Shops: write a one-page check sheet for each PT 33. It should cover the patient identity, the diagnosis, the quantity, the number of days (30 at most) and the prescriber’s profession. Use it before every sale, so incomplete forms are caught before the flower leaves the counter.
- Shops: file prescriptions by date and keep each one for one year. Then you can show an inspector the matching prescription for any sale.
- Shops and patients: check the prescriber’s licence or certificate with the body listed in the table above. This confirms the prescriber is one of the seven groups and that the licence is current.
- Growers: ask each outlet that buys your flower to confirm in writing that it holds a sale licence and sells only against a PT 33. This lowers the risk that your crop ends up in an unlawful sale.
- Everyone: read the Notification itself in the Royal Gazette (ราชกิจจานุเบกษา). Then you can check dates and wording against the original. Thai Cannabis Law and Compliance explains how to find the legal texts.
If you have a question about a PT 33 you have written, received or dispensed, post it below this topic. Remove patient names and ID numbers before you post.
References
- Thai Traditional Medicine Protection Act B.E. 2542 (1999)
- Notification of the Ministry of Public Health Re: Controlled Herbs (Cannabis), B.E. 2568 (2025)
- Ministerial Regulation on Cannabis or Hemp Extracts B.E. 2569 (2026)
- Ministerial Regulation on Controlled Herbs (No. 2) B.E. 2569 (2026)
- Ministerial Regulation on licensing for research, export, sale and processing of controlled herbs, B.E. 2559 (2016), Royal Gazette vol. 133 part 103 Kor, 9 December 2016