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NC3Rs | 20 Years: Pioneering Better Science

Acute toxicity testing

Reducing and refining acute toxicity tests in the pharmaceutical and chemicals industries.


Acute toxicity tests are used to determine the lethal dose/concentration of a substance that causes death in 50% of the test population (LD/LC50) during short-term exposure. They are the only standardised toxicity tests where death is the intended endpoint. We have provided recommendations to support reduction and refinement of these tests through in-house data analysis projects, supported by expert working groups.

Adoption of the Fixed Concentration Procedure for acute inhalation studies

Applying the 3Rs in fish acute toxicity testing

Fish acute toxicity studies are the most widely conducted ecotoxicology test. They are currently required to meet global regulations across many chemical sectors before products can be marketed, including agrochemicals, biocides, and industrial chemicals. 

Read more about this work on our environmental safety testing page.

Single dose acute toxicity studies

Redundancy in the acute toxicity testing of chemicals

Identifying opportunities to waive requirements for acute toxicity testing of chemicals and use alternative approaches.

You can read more about this project on our project page: Redundancy in the acute toxicity testing of chemicals.

Keep up to date with the latest news from the NC3Rs Toxicology and Regulatory Sciences programme.