Under federal law, how much pseudoephedrine you can buy is capped at 3.6 grams of pseudoephedrine base per day and 9 grams per 30 days, no matter how many pharmacies or transactions you use. Some states set lower limits, and Mississippi requires a prescription. Every sale is logged and, in most states, checked against a real-time database that will block a transaction before you go over.
The Federal Daily and Monthly Caps
The Combat Methamphetamine Epidemic Act of 2005 regulates retail sales of pseudoephedrine, ephedrine, and phenylpropanolamine because each can be diverted to make methamphetamine. Two hard caps apply to every buyer in the country:
- 3.6 grams of pseudoephedrine base per day, across all stores and all transactions.1Office of the Law Revision Counsel. 21 U.S. Code 830 – Regulation of Listed Chemicals and Certain Machines
- 9 grams of pseudoephedrine base per 30 days. Knowingly going over this is a federal criminal offense.2Office of the Law Revision Counsel. 21 USC 844 – Penalties for Simple Possession
Purchases made by mail or from a mobile retail vendor (like a kiosk at a shopping center or airport) are limited to 7.5 grams per 30 days within that same 9-gram overall cap.3Drug Enforcement Administration. General Information Regarding the Combat Methamphetamine Epidemic Act of 2005 Order online and the shipped portion of your monthly total cannot exceed 7.5 grams, even though your in-person ceiling is higher.
What Those Grams Look Like on a Sudafed Box
Boxes are labeled in milligrams of pseudoephedrine hydrochloride or sulfate, not in grams of “base.” Each gram of hydrochloride contains about 0.82 grams of base; each gram of sulfate contains about 0.77 grams of base.4U.S. Department of Justice Drug Enforcement Administration. Conversion Factors for Controlled Substances The pharmacy’s system does the conversion for you.
To make the numbers concrete: a common 12-hour Sudafed caplet contains 120 mg of pseudoephedrine hydrochloride. The 9-gram monthly base limit works out to roughly 90 of those caplets, or about four and a half 20-count boxes in a 30-day window. For regular-strength 30 mg tablets, the monthly cap allows several hundred. If you are treating your own cold, you will not come close. Buying for a whole household in flu season, or hitting several pharmacies in a short stretch, is where the ceiling starts to bite.
How the Pharmacy Enforces the Limit
Pseudoephedrine products must be kept behind the counter or in a locked cabinet. You cannot pull a box off an open shelf.5U.S. Department of Justice Drug Enforcement Administration. Combat Methamphetamine Epidemic Act of 2005 (CMEA) Requirements
ID and Logbook
You have to show a state- or federal-issued photo ID. The pharmacy records your name, address, the date and time, the product, and the quantity in a written or electronic logbook, and you sign it. Retailers keep those records for at least two years.5U.S. Department of Justice Drug Enforcement Administration. Combat Methamphetamine Epidemic Act of 2005 (CMEA) Requirements
Real-Time Tracking Across Pharmacies
Roughly 29 states use the National Precursor Log Exchange (NPLEx), which records purchases in real time across participating pharmacies. Before ringing up the sale, the pharmacy sends the transaction to NPLEx, which checks your recent history. If the sale would put you over the limit, the system issues a stop-sale alert and the pharmacy cannot complete it. Some states also block buyers with certain drug-related felony convictions. You will know at the register whether the purchase can go through.
One Small Exception
A single package containing no more than 60 mg of pseudoephedrine does not have to be entered in the logbook. It still must be sold from behind the counter, and it still counts toward your daily and monthly caps.6U.S. Food and Drug Administration. Legal Requirements for the Sale and Purchase of Drug Products Containing Pseudoephedrine, Ephedrine, and Phenylpropanolamine
State Rules That Cut the Limit or Require a Prescription
Federal law is a floor. States can go stricter, and pharmacies follow whichever rule is tighter. The main variations:
- Some states set daily or monthly gram caps below the federal numbers.
- Mississippi requires a valid prescription before a pharmacy can dispense pseudoephedrine at all. Oregon used to have the same rule but has since replaced it with monthly purchase limits.
- A handful of states classify pseudoephedrine as a Schedule III or Schedule V controlled substance, layering additional dispensing rules on top of the federal behind-the-counter framework.
Ask the pharmacist if you are not sure what applies where you live. The tracking system will enforce your state’s cap automatically. The one place this matters practically is if you buy in more than one state during the same 30 days and one of those states has a lower ceiling than the federal number.
Penalties for Going Over
Knowingly buying more than 9 grams of pseudoephedrine base in 30 days is a federal criminal offense, and the penalties climb with prior convictions:2Office of the Law Revision Counsel. 21 USC 844 – Penalties for Simple Possession
- First offense: up to one year in prison and a minimum fine of $1,000.
- With one prior drug or chemical conviction: 15 days to two years and a minimum fine of $2,500.
- With two or more prior drug or chemical convictions: 90 days to three years and a minimum fine of $5,000.
Those are minimum fines; courts can impose more. The prior convictions that trigger the higher tiers include any drug, narcotic, or chemical offense under federal or state law, not just prior pseudoephedrine violations.
False Names and Borrowed IDs
The logbook itself must display a warning that false entries can be prosecuted under 18 U.S.C. ยง 1001, which covers false statements in matters within federal jurisdiction and carries up to five years in prison.7Office of the Law Revision Counsel. 18 U.S. Code 1001 – Statements or Entries Generally Lying on the logbook is treated far more seriously than simply going over the purchase cap.