Bringing Medication from Mexico to the US: The Rules at San Ysidro, Otay Mesa and the Airport
A practical guide for San Diego and California patients, written by a board-certified psychiatrist in Tijuana, 15 minutes from the San Ysidro border crossing.
The short answer
You can usually bring prescription medication from Mexico into the US if it is for your own use, stays in its original container, is declared to CBP and comes with a prescription or doctor's note; non-controlled drugs are generally limited to about a 90-day supply, and controlled drugs bought abroad to 50 dosage units in total.
- Declare everything, even a single box, at San Ysidro, Otay Mesa or the airport.
- Antidepressants such as sertraline, escitalopram, fluoxetine and bupropion aren't US controlled substances: up to about 90 days.
- Clonazepam and ADHD stimulants are controlled: a US resident may bring no more than 50 tablets or capsules combined (21 CFR 1301.26).
- Never mail it, never bring someone else's medication, and never buy unregistered products such as "Adderall" in Mexico.
01 · The law
Is it legal to bring prescription medication from Mexico to the US?
Usually yes, for your own use and in limited amounts. The FDA says importing drugs for personal use is illegal in most circumstances, but it can allow it, and CBP's travel guidance accepts personal quantities with a prescription.
FDA's personal importation policy (page updated August 2025) lists when officers may let a medicine in: the person affirms in writing it's for personal use, the quantity "is generally not more than a three month supply," and they show a US doctor's name or "evidence that the product is for the continuation of a treatment begun in a foreign country."1 CBP adds its own rule of thumb for travelers: no more than a 90-day supply.2
"Travelers must declare all medicine and similar products when entering the United States."
US Customs and Border Protection, guidance for international travelers
02 · Quantities
How much medication can you bring back from Mexico?
About a 90-day supply of a non-controlled medicine, and no more than 50 dosage units in total of controlled medicines bought abroad. The 50-unit cap comes from 21 CFR 1301.26 and applies to US residents.3
| Drug type | Mexican prescription | US status | How much |
|---|---|---|---|
| Antidepressants: sertraline, escitalopram, fluoxetine | Refillable, not retained | Not controlled | About 90 days |
| Bupropion (Wellbutrin) | Retained since July 14, 2026; two boxes at most | Not controlled | About 90 days |
| Benzodiazepines: clonazepam and others | Retained (Group III) | Schedule IV | 50 units, all controlled drugs combined |
| ADHD stimulants: methylphenidate, lisdexamfetamine | Special barcoded prescription | Schedule II | 50 units, all controlled drugs combined |
| "Adderall" sold in Mexico | Not registered with Cofepris (Mexico's drug regulator) | Schedule II | Don't buy it |
US schedules from the DEA's October 2026 controlled substances list;4 Mexican prescription types from the Ley General de Salud, Articles 226, 245 and 251.5
Clonazepam twice a day: 50 tablets last 25 days. Methylphenidate once a day: about 7 weeks. Both together: 30 of each is 60 units, over the limit, because the cap counts all controlled drugs combined. The cap doesn't apply to controlled medicine filled in the US with a DEA-registered prescriber's prescription.
03 · Documents
What documents do you need to cross the border with medication?
Carry the medicine in its original container plus a copy of the prescription or a doctor's letter. CBP says "a valid prescription or doctor's note is required on all medication entering the U.S."2
- Original container with its label. For controlled drugs, the DEA's May 2026 "Traveling With Medication" sheet asks that the label show the drug's name and schedule, or the pharmacy and prescription number.6
- A copy of your Mexican prescription. It's the "evidence" of a treatment begun abroad that FDA's policy mentions, and it shows the doctor's cédula profesional (Mexican license number).
- A photocopy of any retained prescription. For clonazepam, stimulants and bupropion the Mexican pharmacy keeps the original, so copy it before you hand it over.
- Your receipt, and an English note from your doctor if the prescription is only in Spanish.
04 · Limits
What medication can you never bring from Mexico?
Never bring medicines the FDA hasn't approved, more than personal-use quantities, someone else's medication, or anything shipped by mail. The DEA warns that drugs legal abroad but not approved for US use are "subject to confiscation" and can bring severe penalties.6
- Mail or courier: the DEA exemption in 21 CFR 1301.26 covers a traveler carrying controlled medicine across, not packages.3 Carry every medicine yourself.
- Medicine for family or friends: FDA and DEA rules refer to the traveler's own personal use.
- Unregistered or street products: a UCLA-led study published in 2023 found that 9 pills sold as "Adderall" in northern Mexico pharmacies contained methamphetamine.7
- Over 50 controlled units or clearly more than 90 days of anything else.
05 · Declaring
What happens if you don't declare medication at the border?
Undeclared medication can be seized, and you can be fined. Under 19 U.S.C. 1497, an undeclared article is subject to forfeiture plus a penalty equal to its value, or for a controlled substance $500 or 1,000% of its value, whichever is greater.8
Trusted traveler membership is also at risk: a CBP press release describes Global Entry members facing revocation after failing to declare purchases.9 SENTRI, the lane many San Diego commuters use, is part of the same family of CBP trusted traveler programs. Declaring takes one sentence: "I have prescription medication for my personal use."
06 · By air
Are the rules different if you fly from Mexico?
No. The federal rules are the same by air: CBP inspects you when you arrive, and 21 CFR 1301.26 isn't limited to land crossings. Only the security screening differs.
- Tijuana airport and CBX: Cross Border Xpress, open since 2015, lets ticketed Tijuana airport passengers walk to a terminal in Otay Mesa, where a CBP officer inspects every traveler.10
- TSA screening: TSA allows medication in pill form "in unlimited amounts as long as it is screened" and doesn't require prescription bottles, but notes that state labeling laws still apply.11
- Pack it in your carry-on, in original containers, with the prescription copy on top.
- Heading south first? Mexico's foreign ministry asks travelers to declare personal medicine and carry a prescription or doctor's letter translated into Spanish.12
07 · Checklist
What should you check before crossing with medication?
Check five things before you leave the pharmacy: the quantity, the containers, the papers, whose medicine it is and how you'll say it to the officer.
- Count it. Up to about 90 days of non-controlled medicine; no more than 50 units of controlled medicine bought in Mexico, all combined.
- Keep original boxes or bottles. No pill organizers or loose blister strips for controlled drugs.
- Pack the papers: prescription copy, receipt, and copies of any prescription the pharmacy kept.
- Only your own medicine, under your own name.
- Keep it reachable, in the car's front seat area or your carry-on, not buried in a trunk.
- Declare it to the first CBP officer you speak with, before you're asked.
- Answer plainly. If you're sent to secondary inspection, show the boxes and papers.
"The rules are stricter than most people expect but simple to follow: the original box, a copy of the prescription, a supply you can justify, and say it out loud to the officer."Dr. B. Ernesto Cedillo Ramírez, psychiatrist in Tijuana
08 · Care with me
Can a Tijuana psychiatrist write a prescription you can carry across the border?
Yes. A Mexican-licensed psychiatrist can write the prescription a Mexican pharmacy needs and that FDA and CBP guidance expects you to carry. California pharmacies can't fill it, though Texas and Arizona can for non-controlled drugs.
In my practice, every prescription carries my full name, cédula numbers, the generic name, dose and duration, so it reads clearly at the pharmacy and at the port of entry. I don't prescribe controlled medication by request or without an evaluation. A 60-minute first visit costs $125; follow-ups cost $105, by video only while you're physically in Mexico.
Dr. B. Ernesto Cedillo Ramírez, psychiatrist in Tijuana: New City Medical Plaza, P.º del Centenario 9580, Suite 24, 25th floor, Zona Urbana Río Tijuana, 22010 Tijuana, B.C., 15 minutes from the San Ysidro border crossing. WhatsApp +52 664 484 2218. Monday, Tuesday, Wednesday and Friday 10:00 to 18:30; Saturday 10:00 to 15:00.
Key terms
- Dosage unit
- A dosage unit is a single tablet, capsule or other individual dose of a medicine.
- Controlled substance
- A controlled substance is a drug the DEA places in Schedules I to V, such as clonazepam or methylphenidate.
- Personal importation
- Personal importation is bringing a medicine into the US for your own treatment, in limited quantities.
- Secondary inspection
- Secondary inspection is the more detailed CBP review a traveler may be sent to after the first booth.
09 · FAQ
Frequently asked questions about bringing medication from Mexico
How much medication can I bring back from Mexico?
Generally up to a 90-day supply of a non-controlled medicine, such as an antidepressant, for your personal use. For controlled medicines bought abroad, like clonazepam or methylphenidate, a US resident may bring no more than 50 dosage units in total, all controlled drugs combined, under 21 CFR 1301.26.
Do I have to declare medication at the border?
Yes. CBP says travelers must declare all medicine when entering the United States, including prescription drugs bought legally in Mexico. Tell the officer at San Ysidro, Otay Mesa or the airport, keep the medicine in its original container and carry a copy of the prescription or a doctor's note.
Can I bring clonazepam from Mexico?
Yes, within limits. Clonazepam is a Schedule IV controlled substance in the US, so a US resident may bring no more than 50 tablets of controlled drugs bought abroad, all combined. It needs a retained Mexican prescription, so photocopy it before the pharmacy keeps it, and declare it in the original box.
Can I mail medication from Mexico to the US?
No, don't. The DEA personal-use exemption covers controlled medicine a traveler carries across the border, not packages, and the FDA says importing drugs for personal use is illegal in most circumstances. Carry your medication yourself, declare it and stay within personal-use quantities.
Can you bring Adderall to Mexico?
Possibly, with paperwork. Mexico's foreign ministry tells travelers to carry a prescription or doctor's letter translated into Spanish, declare medicine on arrival and bring only what the stay requires. Amphetamine is controlled in Mexico and Adderall isn't sold there, so confirm with a Mexican consulate first. Coming home, US-filled Adderall isn't subject to the 50-unit limit.
Is Adderall over the counter in Mexico?
No. Adderall isn't sold legally in Mexico at all, with or without a prescription, and no ADHD medication is legally sold over the counter there. Pills sold as Adderall in Mexican pharmacies have been found to contain methamphetamine. Legal alternatives exist with a special Mexican prescription.
Can I bring medication from Mexico for someone else?
No. Federal rules for travelers cover medicine for your own personal use, under your own name, in personal quantities. Bringing a parent's or friend's medication can lead to seizure at the port of entry. The person who takes the medicine should carry it across with their own prescription.
Keep reading
Related pages
Dr. B. Ernesto Cedillo Ramírez, MD
Board-certified psychiatrist in Tijuana · Zona Río
I trained in medicine and psychiatry at UNAM, with my residency at Hospital Psiquiátrico Fray Bernardino Álvarez in Mexico City, and I'm board certified by the Consejo Mexicano de Psiquiatría. Many of my patients cross from San Diego for care in English or Spanish.
Céd. Prof. 11206254 · Céd. Esp. 13577158. Here's how to verify them.
Sources
References
- FDA. Personal Importation, current as of August 18, 2025. fda.gov
- CBP. What international travelers should know before they go. cbp.gov
- 21 CFR § 1301.26, Exemptions for personal medical use. law.cornell.edu
- DEA Diversion Control. Controlled Substances, Alphabetical Order, October 2026. deadiversion.usdoj.gov
- Ley General de Salud (Mexico), Articles 226, 245 and 251, last amended January 15, 2026. diputados.gob.mx
- DEA. Traveling With Medication, May 2026. dea.gov
- UCLA Health, February 2, 2023. Counterfeit pills sold in Mexican pharmacies. uclahealth.org
- 19 U.S.C. § 1497, Penalties for failure to declare. law.cornell.edu
- CBP. Press release on Global Entry revocation for failure to declare. cbp.gov
- CBP, July 22, 2015. CBP partners on new cross-border terminal, Cross Border Xpress. cbp.gov
- TSA. Can you pack your meds in a pill case? tsa.gov
- Embassy of Mexico (SRE). Medicines: bringing personal medicines into Mexico. sre.gob.mx
Need a prescription you can carry with confidence?
Book a first visit in English or Spanish in Zona Río, 15 minutes from the San Ysidro crossing.
This guide summarizes federal rules and isn't legal advice. CBP officers have final discretion at every port of entry, and state laws may also apply. Updated . Crisis: in Mexico, Línea de la Vida 800 911 2000 or 911; in the US, call or text 988.