Schedules of Controlled Substances

Controlled substances are placed into five schedules based on their medical use, potential for abuse, and safety or dependence liability. Schedule I substances have high abuse potential and no accepted medical use (e.g., heroin, LSD). Schedule II substances have high abuse potential but accepted medical use (e.g., morphine, fentanyl, amphetamine).

Schedules III through V have progressively lower potential for abuse. The DEA may add, remove, or transfer substances between schedules through rulemaking. Emergency scheduling authority allows temporary placement for up to two years when necessary to avoid imminent hazard to public safety.