# controlled substances

CEFR C1 · Compound

Source: https://englishreference.com/word/controlled-substances
Updated: 2026-08-02

## Definition

drugs or chemicals that are strictly limited by the government because they can be dangerous or addictive.

For teachers: a legal classification for drugs and chemicals whose manufacture, possession, and use are regulated by a government. This term is typically used in a legal or pharmaceutical context to refer to narcotics, stimulants, and other substances with a high potential for abuse.

## Examples

- The pharmacy keeps all controlled substances in a locked cabinet.
- It is illegal to transport controlled substances across the border without the proper medical documentation and permits.
- The legislative overhaul aimed to reclassify several synthetic compounds as controlled substances to curb the rising rates of accidental overdoses.

## Usage notes

- usually used in the plural; common in legal, medical, and law enforcement contexts.
- Teaching tip: contrast with 'illegal drugs' — while all illegal drugs are controlled substances, many controlled substances are legal when used with a valid prescription.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.