Bringing Medications from the US to Mexico: Legal Guide [2026]

Many people don’t give much thought to their medications when they travel. They set up their pill minder for a week or two and pack it in their luggage. We often get complacent about this when we're on vacation or a business trip. However, there are specific rules for traveling with medications. This is especially true when your travel takes you internationally. So, it's important to understand the rules around bringing medications from the United States into Mexico.

Why Understanding the Rules Matters

Going through customs when entering a foreign country has a long history. Originally, customs was the practice of collecting fees or taxes on goods entering the country. The practice evolved to include checking items and people for safety purposes and ensuring everyone is complying with local laws.

Taking medication into a foreign country falls under the authority of the country's customs agency to protect the safety and health of its citizens. In Mexico, the Secretary of Health (Secretaría de Salud) is the agency responsible for national health policy. This includes regulating drugs and medical devices. They oversee the regulation of the import and export of medical products under the General Health Law (Ley General de Salud).

Mexico’s Official Rules for Limited-Use Personal Medications

When traveling to Mexico, you may bring up to a 90-day supply of medication for personal use. More than that amount raises concern for potential drug trafficking. Legally, you must bring a prescription or a letter from their general practitioner that states:

• The amount of the substance required by the patient during their stay

• The amount they are bringing into the country

• The daily dose

What Medications Can You Bring?

All medications must be in their original labeled bottle. It’s recommended that you also bring a written copy of the prescription. You may bring vitamins and supplements as long as the amount is reasonable. Think the same 90-day supply rule.

You can bring most over-the-counter medications, with a few exceptions. These exceptions include medications that contain stimulants, such as pseudoephedrine and codeine. Over-the-counter medications with these ingredients include inhalers and some allergy and sinus medications.

What You Cannot Bring Without Extra Documentation

Mexico strictly monitors and limits the transport of controlled substances, such as certain stimulant medications used for ADHD and narcotics used for pain management. You will need extra documentation to present to customs officials when entering the country with these medicines.

Bring a letter from your doctor on their letterhead. The letter must state:

• Your name

• Medication name

• Dosage

• The daily amount you will take

• The amount needed for your trip

Please have the letter and the prescription for the medication translated into Spanish. The prescription must match the bottle.

Don’t bring more than your doctor has prescribed for your trip. For many travelers, you may only receive a 30-day prescription from your doctor. If you bring more medication than you need for your trip, or more than your doctor authorized, customs may confiscate it.

There are prohibited items you cannot bring into Mexico. Dried medicinal herbs are not allowed. Narcotics without a prescription and all the correct documentation are not allowed. Marijuana, in any form, is not allowed.

Avoid trying to take:

• Marijuana (Cannabis Indica) or marijuana seeds or spores, even if mixed with other seeds

• Heroin, base, or Diacetylmorophine hydrochloride (morphine derivative)

• Medicinal preparations based on marijuana (Cannabis Indica)

• Opium juices or extracts prepared for smoking

• Medical preparations based on acetylmorphine, its salts, or derivatives.

Required Documentation for Prescription Medications

You must declare the prescriptions at your port of entry when going through customs. The prescriptions must have:

• Name of the doctor prescribing the medication

• Their signature

• Contact details (phone, address)

The medication must not exceed the amount needed for your stay. If you are staying long-term, plan on no more than a 90-day supply of any medication. All prescriptions must include a Spanish translation, and the prescription must match the bottle label. If you have any concerns about whether your specific medication is allowed, contact the Mexican consulate in your area.

What Happens During Customs Screening

When you go through customs, the officers will check your passport and visa. Biometrics scans are now common at most airports, and Mexico is using the “traffic light” system. They screen for any security flags, such as immigration violations, overstays, criminal records, and watchlists. If you are considered safe, you will receive a green light. A yellow or red light will lead to further screening.

If you are pulled aside for an inspection, they are looking for prohibited and undeclared items. They can search your luggage or vehicle. Secondary searches happen if you’re flagged by the system, act suspiciously, or if they find anything inappropriate (undeclared medications, forbidden items, etc.).

How to Avoid Problems at the Border

To avoid problems when entering Mexico with your medications, ensure you have all the required documentation. Declare your medications, especially if you are bringing controlled substances or large quantities. Don’t try to sneak in medications that are forbidden. Random searches occur at the border when you pass through customs, both when driving and flying.

Pretty commonly, travelers overlook the official rules for bringing medications from the U.S. into Mexico. You will hear many expats say the formalities aren’t necessary. Maybe. Or maybe they’ve just been lucky.

In the past, it was easier to get around these legal requirements. However, Mexico is getting stricter and doing a better job of enforcing its rules. When deciding what you want to do, consider the cost of replacing your medications or going without them if they are confiscated by customs.

If you need more information, I provide additional details in the Complete Healthcare Guide for Mexico Workbook. The workbook is a comprehensive guide to your healthcare transition from the U.S. to Mexico.