Final answer:
An individual can purchase no more than 3.6 grams of pseudoephedrine per day and no more than 9 grams over 30 days, as regulated by the Combat Methamphetamine Epidemic Act of 2005 in the United States.
Step-by-step explanation:
In the United States, the Combat Methamphetamine Epidemic Act of 2005 regulates the purchase of pseudoephedrine due to its use as a precursor in the illicit production of methamphetamine. According to this federal regulation, an individual is limited to buying no more than 3.6 grams of pseudoephedrine per day and no more than 9 grams in a 30-day period. This includes purchases from all retailers, not just a single location. These regulations require pharmacies and other retail outlets to keep personal information about purchasers for at least two years.
It is important for individuals who legally require pseudoephedrine for its intended medicinal purposes, such as congestion relief, to be aware of these purchasing limits. The limitations are part of broader efforts to prevent the diversion and misuse of pseudoephedrine in the illegal manufacture of methamphetamine, an ongoing public health concern.