A drug's schedule determines whether it can be prescribed, researched, sold or taxed under federal law, directly affecting patients, businesses and consumers.
It's the federal government's strictest drug category, meant for substances officials say are highly addictive and have no approved medical purpose.
Marijuana's Schedule I status means state-legal cannabis businesses still face federal banking restrictions, tax penalties and possible prosecution.
Congress established the five schedules in 1970, and the Drug Enforcement Administration, with input from the Food and Drug Administration, can add, remove or reclassify substances.
Changing a drug's schedule requires a formal rulemaking process including scientific review, public comment and final agency action, as seen in the DEA's 2024 proposal to move marijuana to Schedule III.
A look at how federal marijuana law works, what states have done, and the arguments shaping the legalization debate.
Read the guide →Federal law still classifies marijuana as a Schedule I drug even as most states have moved to allow some legal use.
Read the brief →