Controlled substance schedules I to V and the official DEA list
A controlled substance schedule is one of five US categories (I to V) set by the Controlled Substances Act. The binding list is 21 CFR Part 1308.
A controlled substance schedule is one of five federal categories, Schedules I to V, under the Controlled Substances Act (CSA). Each schedule is set by abuse potential, accepted medical use in the US and dependence liability, under 21 U.S.C. 812(b). Schedule I is the most restricted and Schedule V the least.
The official list is 21 CFR Part 1308. DEA changes it through Federal Register rules.
What is a controlled substance?
Under 21 U.S.C. 802(6), a controlled substance is "a drug or other substance, or immediate precursor, included in schedule I, II, III, IV, or V of part B of this subchapter." The definition excludes distilled spirits, wine, malt beverages and tobacco.
So a substance is controlled because it is listed. Pharmacology alone doesn't make it controlled. There is one exception: controlled substance analogues.
The five DEA drug schedules
Each schedule has its own statutory criteria in 21 U.S.C. 812(b). The examples and DEA drug codes come from 21 CFR Part 1308.
| Schedule | Statutory criteria | Examples (DEA drug code) |
|---|---|---|
| I (1308.11) | High potential for abuse; no currently accepted medical use in the US; lack of accepted safety for use under medical supervision | Heroin 9200, LSD 7315, psilocybin 7437, marihuana 7360 (exceptions below) |
| II (1308.12) | High potential for abuse; accepted medical use, or accepted use with severe restrictions; abuse may lead to severe psychological or physical dependence | Fentanyl 9801, oxycodone 9143, cocaine 9041, methamphetamine 1105, amphetamine 1100 |
| III (1308.13) | Abuse potential less than Schedules I and II; accepted medical use; abuse may lead to moderate or low physical dependence or high psychological dependence | Ketamine 7285, buprenorphine 9064, anabolic steroids 4000 (includes testosterone) |
| IV (1308.14) | Low abuse potential relative to Schedule III; accepted medical use; limited dependence relative to Schedule III | Alprazolam 2882, diazepam 2765, zolpidem 2783, tramadol 9752 |
| V (1308.15) | Low abuse potential relative to Schedule IV; accepted medical use; limited dependence relative to Schedule IV | Pregabalin 2782, lacosamide 2746, brivaracetam 2710 |
DEA's Drug Scheduling page gives brand-name examples too. It lists Xanax, Valium and Ambien in Schedule IV and Tylenol with codeine in Schedule III. Use the CFR to check a specific product's status, rather than relying on this explainer.
A schedule is not a danger ranking. The statutory criteria mix abuse potential, medical use, dependence and, for Schedule I, accepted safety. The CFR lists fentanyl in Schedule II and psilocybin in Schedule I.
Where the official controlled substance list lives
The binding text is 21 CFR Part 1308, one section per schedule: 1308.11 for Schedule I through 1308.15 for Schedule V. Each section is split into lettered categories such as opiates, hallucinogens, depressants and stimulants. When checked on 1 October 2026, eCFR showed Part 1308 up to date as of 29 September 2026.
Every controlled substance or basic class has a drug code, the Administration Controlled Substances Code Number. Under 21 CFR 1308.03, it identifies the substance on registration certificates and order forms. Quota applications, import and export permit applications and DEA Form 236 must include it. Otherwise it is not required for any purpose.
DEA Diversion Control also publishes working lists, often called the Orange Book. One of them is Controlled Substances in Alphabetical Order, dated 27 August 2026 in its footer. The schedules index page links the full Orange Book (August 2026) and the exemption lists, including a Table of Exempted Prescription Products dated 1 April 2026. Two other exemption lists are the Exempt Chemical Preparations list (2 April 2026) and the Exempt Anabolic Steroid Products list (5 November 2020).
But these PDFs are not the binding text. They help with name searches. The CFR entries determine which salts, isomers and preparations are covered. Check the relevant exemption list too. For a compliance decision, also check Federal Register rules published after the eCFR date.
A published rule may not be in force yet. The diphenidine rule was published on 21 September 2026 but takes effect on 21 October 2026.
How a substance gets scheduled, rescheduled or removed
21 U.S.C. 811 sets the procedure. The Attorney General's authority is delegated to the DEA Administrator. A proceeding can start on DEA's own motion, at the request of the Secretary of Health and Human Services (HHS), or on a petition from any interested party. Rules are made on the record after an opportunity for a hearing.
In the ordinary procedure under 811(b), DEA first gets HHS's scientific and medical evaluation and scheduling recommendation. That recommendation binds the Attorney General on scientific and medical matters. If HHS recommends against control, the substance cannot be controlled through that procedure. The decision weighs eight factors in 811(c), including abuse potential, abuse patterns, public-health risks, dependence and immediate-precursor status.
Other routes do not follow that full procedure.
- Temporary scheduling under 811(h) avoids an imminent hazard to public safety. It can only place a substance in Schedule I, and the order expires after two years, extendable by up to one year while permanent proceedings run. Bromazolam is a current example: placed temporarily on 16 March 2026, running to 16 March 2028. Temporary listings sit in 1308.11(h).
- Under 811(d)(1), where US treaty obligations require control, DEA can place a substance in the schedule it considers most appropriate without the 812(b) findings or the usual procedure.
- Congress can schedule by statute. The HALT Fentanyl Act, signed 16 July 2025, put the class of fentanyl-related substances permanently in Schedule I by amending 21 U.S.C. 812(c). The Schedule II entry for fentanyl, code 9801, is separate from that class.
An unlisted substance can still be a controlled substance analogue under 802(32). The test covers substantial structural similarity to a Schedule I or II substance and substantially similar or greater stimulant, depressant or hallucinogenic effects. Approved drugs and some investigational substances are excluded. To the extent intended for human consumption, an analogue is treated as Schedule I (813).
Recent changes to the schedules
Do not treat all marijuana as Schedule III. DEA proposed moving all marijuana to Schedule III in May 2024. Executive Order 14370 of December 2025 told the Attorney General to speed up that rulemaking, but it did not reschedule anything itself.
The final rule of 28 April 2026 used the treaty route. It moved marijuana, marijuana extract and naturally derived delta-9-THC to Schedule III only when they are in an FDA-approved product or subject to a state medical marijuana license. Those Schedule III entries may be imported or exported only under a permit. All other marijuana is still Schedule I, and 1308.11(d) still lists it. A hearing on the rest was noticed the same day. On 29 September 2026 the Chief Administrative Law Judge stayed that case pending a motion and further briefing, with government responses due 13 October 2026.
Other recent actions:
- Cipepofol went into Schedule IV by interim final rule, effective 27 August 2026.
- DEA has proposed moving suvorexant, lemborexant and daridorexant from Schedule IV to V. That is a proposal only.
- Schedule I additions keep coming, such as 4-fluoroamphetamine in January 2026 and diphenidine, effective 21 October 2026.
The CFR and statute can be out of step. The eCFR text still shows fentanyl-related substances in temporary paragraph 1308.11(h), code 9850. Read it alongside the HALT Fentanyl Act's amendment to 21 U.S.C. 812(c).
What the schedule changes for registrants
Anyone who manufactures, distributes, dispenses, imports or exports a controlled substance must hold a DEA registration unless exempt (21 CFR 1301.11). Import permits are required for Schedule I and II substances and narcotic substances in Schedules III to V. Export permits cover Schedules I and II, narcotics in Schedules III and IV, and some designated non-narcotics.
Labels carry the schedule symbol, CII or C-II for example, under 21 CFR 1302.03. The word "schedule" isn't needed, but the symbol must be clear and large enough to identify quickly (1302.04).
Prescription rules differ too. Schedule II prescriptions can't be refilled (21 U.S.C. 829(a)), though 21 CFR 1306.12 allows multiple prescriptions covering up to a 90-day supply. Schedule III and IV prescriptions may not be filled or refilled more than six months after issue, and may not be refilled more than five times, unless renewed (21 U.S.C. 829(b); 21 CFR 1306.22).
To look up the schedule, drug code and recent Federal Register actions for a specific substance in one place, you can ask RegAffairs AI, which cites the CFR and DEA rules it answers from.