Primary sources only. Where the official page disagrees with this one, it is right.
Thailand does not have a single medication rule. It has two, written under two different laws, and which one applies to you depends on how your medicine is scheduled — not on how serious it feels. Getting this wrong in either direction costs you: one way you skip a permit you needed, the other way you spend three weeks applying for a permit that does not exist for your drug.
Under the Narcotics Act B.E. 2522, a traveller carrying a Category 2 narcotic must hold a permit issued by the Thai FDA before travelling. Category 2 is where the opioids sit: codeine, dihydrocodeine, dextropropoxyphene, fentanyl, hydrocodone, hydromorphone, methadone, morphine, oxycodone and pethidine are the examples the FDA itself gives.
• Apply around two weeks before you travel, and not more than one month ahead. Both ends of that window matter — too early is also refused.
• Form IC-1 is the application to carry in; OC-1 is to carry out.
• Limit: 30 days of prescribed usage.
• On arrival you must present the medicine, the documents and the permit at the Customs
Department Red Channel. Not the green one. Walking through the nothing-to-declare lane with
a Category 2 narcotic is the mistake that turns paperwork into an incident.
Under the Psychotropic Substances Act B.E. 2518, these need no permit at all. A certificate or prescription from the prescribing physician is enough, up to 30 days of prescribed usage. The FDA goes further: carried that way, they are considered personal belongings, and you do not have to declare them at the Red Channel.
This is the half nobody gets right. The substances here include zolpidem, methylphenidate, midazolam, nitrazepam, phentermine, temazepam, triazolam, buprenorphine and ketamine (Category 2); pentazocine and the barbiturates pentobarbital and amobarbital (Category 3); and alprazolam, bromazepam, chlordiazepoxide, clonazepam, clorazepate, diazepam, lorazepam, oxazepam and phenobarbital (Category 4). Pseudoephedrine is in Category 2 — which means the cold medicine everyone assumes is banned is in fact allowed with a prescription, and the real problem is that almost nobody has a prescription for a cold medicine they bought off a shelf.
Narcotics of Category 1 and psychotropics of Category 1 are prohibited, and determined to have no medical use in Thailand. The FDA's own examples are amphetamine, dexamphetamine, cathinone and THC. No permit is issued, no letter helps, and no amount of lead time changes it. If your medicine is here, the only useful conversation is with your prescriber about an alternative — which is the FDA's own advice too.
The specific pages: Adderall and amphetamine · Sudafed and pseudoephedrine.
The Thai FDA guidance puts the ceiling at 30 days for both routes. A Royal Thai Embassy page states 90 days for narcotics and 30 for psychotropics. We use the stricter figure and we are telling you the two official pages disagree, because you are the one standing at the counter.
For the Route A permit, the Thai FDA asks for three things: the application form, a medical prescription, and — this is the one — a certificate issued by a competent authority of the country of departure confirming that you are legally authorised to carry the medication for personal use. That is a government document, not a note from your doctor, and the FDA publishes a model form for it. Start on that first; it is the step with the longest tail.
Both routes require the same content in the prescription or physician's certificate:
• your name and address
• the identified medical condition
• the name of each medication and why it was prescribed
• the posology and the total amount prescribed
• the prescribing physician's name, address and licence number
Our letter template carries these fields. Keep the prescription or certificate with you for the whole stay, not just at the airport.
• Keep the medicine in its original prescription container with the contents clearly
marked.
• You may not sell or supply your medication to anyone else in Thailand.
• Check the category before each trip rather than relying on last time — the FDA's
lookup tool at permitfortraveler.fda.moph.go.th exists for exactly this.
Questions go to tnarcotics@fda.moph.go.th or +66 2590 7346. One caution on sources: the FDA reorganised this part of its website, and the form-download link printed inside its own guidance document now returns a 404. Start from the portal rather than from any direct form link you find, including an older one of ours if we ever let one rot.
Thai FDA Narcotics Control Division — permit portal for travellers, with the drug-category lookup
Thai FDA — guidance for travellers under treatment carrying personal medications (PDF)
Thai FDA — one-page traveller procedure, four steps (PDF)
Thai FDA — the four psychotropic categories and what is in each
Royal Thai Embassy — restricted medicine, traveller summary
Last checked 2 October 2026. Where the official pages above disagree with this one, they are right and we are out of date.