How many grams of pseudoephedrine can one person purchase per day?

The correct amount of pseudoephedrine that one person can purchase per day is 3.6 grams. This regulation is in place because pseudoephedrine is a key ingredient in the illicit manufacture of methamphetamine. To reduce the risk of misuse, federal law stipulates that individuals can only purchase up to 3.6 grams of pseudoephedrine in a single day, either in a single transaction or aggregated over multiple transactions within that day.

This limitation helps control access to over-the-counter medications containing pseudoephedrine and is part of a broader effort to combat drug abuse and ensure public safety. Pharmacies are required to keep a log of such purchases, which further enhances monitoring and compliance with the law.

When considering the other options, it is important to note that lower amounts would not align with the regulations established, while a higher amount, such as 5 grams, exceeds the permissible daily limit established by law.