Pre-clinical development is a period in development when activities that need to be performed and results to be obtained before a clinical trial in humans can begin.

Typically, both in vitro and in vivo tests will be performed. Areas covered are pharmacology, toxicology, toxokinetics, dose-response studies, genotoxicity, reproductive toxicity and, at a later stage, carcinogenicity studies. These areas are agreed on by the ICH and implemented by the three ICH parties, i.e. Europe, Japan and the US, as their national law.

There is much misinformation about the use of animals in preclinical testing of new drug candidates. Animal testing in the research-based pharmaceutical industry has been reduced in recent years both for cost reasons and in response to protests by animal rights groups. Typically animal testing involves 2 species (often rodent and dog) to determine the absorption, distribution, metabolism, and excretion of the drug. This information is necessary so that safe human testing can commence.