Can I take medications from the UK to the USA?
Yes — UK prescription and OTC medication can travel to the USA in cabin or checked luggage.
Bring medication in original labelled packaging with the prescription where possible. Liquid medication is exempt from the 100ml rule but must be declared at security. Controlled substances (strong painkillers, ADHD medication, sleep medication) need a doctor's letter.
UK 'Pharmacy' or 'POM' medications without an obvious US equivalent — and especially anything containing codeine, pseudoephedrine, or controlled ingredients — can be questioned at the US border. Bring documentation.
Triple check before you pack
Airport security, airline baggage rules, and destination border rules are three different checks. Passing one does not guarantee passing the others.
Essential medicines are usually exempt from the 100ml cabin rule when carried for the journey, with documentation if asked.
Declare medicines at the start of screening. Keep them in original labelled packaging.
Keep essential medication in your cabin bag with the prescription or pharmacist's letter, in case checked luggage is delayed.
Some medicines are controlled at the the USA border. Check the destination's controlled-substances list and carry a prescription.
Cabin — recommended, liquid medication exempt from 100ml
Keep essential medication in cabin baggage in case checked bags are delayed. TSA and UK security exempt prescription liquid medication from the 100ml rule in 'reasonable quantities for the journey'. Declare liquid medication separately at the checkpoint — it may be tested by chemical strip but not opened. Pills, tablets and inhalers are not restricted by quantity in cabin.
Checked — backup supply only
Keep your primary supply in cabin. A backup in checked is sensible for long trips, in original packaging. Never put insulin or other temperature-sensitive medication only in checked — hold temperatures vary.
US customs — declare on the CBP form if asked
Bring medication in original packaging with the pharmacy label and prescription. For controlled substances, carry a doctor's letter stating the medication, dosage and that it is for personal medical use. The FDA allows personal-use quantities (typically up to 90 days' supply) of medications approved in the UK but not in the US, when accompanied by a prescription.
Medications containing pseudoephedrine, codeine, tramadol, or benzodiazepines are scheduled controlled substances in the US and require a doctor's letter. Cannabis-based UK prescriptions (including Sativex, Epidyolex) are NOT permitted into the US under federal law, even with a prescription.
Common mistakes
- Repackaging tablets into a weekly pill organiser without the prescription label — fine at security, problematic at customs.
- Not declaring liquid medication over 100ml at UK security — it gets binned with other liquids.
- Bringing UK-only OTC medication (e.g. co-codamol, sudafed plus) into the US without a doctor's letter.
- Assuming a UK medical-cannabis prescription is recognised at US customs (it isn't).
Pre-flight checklist
- Medication in original labelled packaging
- Copy of UK prescription or repeat slip
- Doctor's letter for controlled substances and unusual medications
- Essential medication in cabin, not checked
- Liquid medication declared at security separately from other liquids
- Temperature-sensitive medication (insulin, biologics) in a cool pack in cabin
Official sources
- UKGOV.UK — Hand luggage restrictions
- UKGOV.UK — Taking medicine abroad
- USTSA — Traveling with medication
- USFDA — Personal importation of medicines and food
- USUS CBP — Prohibited and restricted items
Last reviewed May 26, 2026. Rules can change at short notice. Airport security staff and customs officers have final discretion at the checkpoint or border.
Frequently asked questions
Do I need a doctor's letter for the USA?
Not for routine medication — original packaging plus the prescription label is enough. You DO need a letter for controlled substances (strong painkillers, ADHD medication, sleep medication, benzodiazepines).
Is liquid medication exempt from the 100ml rule?
Yes, in 'reasonable quantities for the journey'. Declare it at the start of security. It may be tested by chemical strip but containers are not opened.
Can I bring UK medical cannabis to the USA?
No. Cannabis remains a Schedule I controlled substance under US federal law. UK prescriptions for Sativex, Epidyolex or other cannabis-based medications are not recognised at the US border.
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Related corridor guides
LiquidLimits.com is a travel planning tool, not an official airport or government source. Rules can change between trips and between terminals. Always check the official airport or aviation security guidance before you travel, and when in doubt pack to the stricter 100ml cabin-bag rule.