The Drug Enforcement Administration (DEA) is a United States Department of Justice law enforcement agency tasked with suppressing the sale of recreational drugs of abuse and enforcing the Controlled Substances Act of 1970. In the act, Congress divided proscribed substances into five schedules (enforced by the DEA) based on a number of factors, including DEA's perceived potential for abuse and whether the Department of Health and Human Services recognizes any legitimate medical uses for the drug. Penalties for possession of illegal drugs vary according to the schedule of a substance.

The DEA has been criticized for placing drugs which many researchers regard as having potential medical uses, such as MDMA, on highly restrictive schedules, even over the objections of many experts in the field of pharmacology and medicine. Critics claim that such decisions are motivated primarily by political factors stemming from the US government's War on Drugs, and that many potential benefits of such substances remain unknown due to the difficulty of conducting scientific research.

Others criticize the very existence of the DEA and the War on Drugs as inimical to the concept of civil liberties; arguing that adults should have the right to put whatever substances they choose into their own bodies.

The DEA has a registration system in place to authorize medical professionals, researchers and manufacturers access to even "Schedule I" drugs. Authorized registrants receive a so called "DEA Number" which is to be solely used for tracking controlled substances. The DEA number, however, is often used by the industry as a general "prescriber" number as a unique identifier for anyone who can prescribe medication.

A valid DEA number consists of[1]:

  • 2 letters and 7 digits
  • the first letter is either an "A" or a "B"
  • the second letter is the initial of the registrant's last name
  • the seventh digit is a "checksum" that is calculated as:
    • add together the first, third and fifth digits
    • add together the second, fourth and sixth digits and multiply the sum by 2
    • add the above 2 numbers
    • the last digit (the one's value) of this last sum is used as the seventh digit in the DEA number

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