# preclinical

/pɹiˈkɫɪnɪkəɫ/ (US) · CEFR C1 · Adjective

Source: https://englishreference.com/word/preclinical
Updated: 2026-10-18

## Definition

happening before a disease shows clear signs, or before a new drug is tested on people. Doctors use it for early lab research and early stages of illness.

For teachers: preceding the appearance of clear symptoms or the stage of testing in humans. Typically describes laboratory and animal research carried out before clinical trials begin.

## Examples

- Scientists do preclinical tests before human trials.
- The new vaccine showed good results in preclinical studies on mice, so the team applied for approval to start human trials.
- Preclinical evidence suggested the compound could slow tumor growth, yet researchers cautioned that laboratory success often fails to predict how patients will respond in later clinical phases.

## Synonyms

presymptomatic

## Antonyms

clinical, symptomatic

## Usage notes

- Typically placed before the noun it modifies, as in 'preclinical trial' or 'preclinical stage'.

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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.