This work examines the use of animals in scientific research across multiple fields, including biomedical, pharmaceutical, industrial and military sectors. It reviews cases such as the Draize eye irritation test and reflects on the extent to which animal suffering is considered justifiable in the pursuit of human health and safety.

The project takes a look at existing regulations, notably European Directive 2010/63/EU, which incorporates the Three Rs principle—Replacement, Reduction and Refinement—to minimise animal suffering. It also analyses the gradual decline in animal use within the European Union and the growing commitment to transparency in this regard in Spain. From a philosophical perspective, the work discusses the contributions of thinkers such as Jeremy Bentham and Peter Singer, who advocate for the moral consideration of animals while denouncing speciesism. Their perspectives emphasise that experiments on animals should only be considered acceptable when they pursue a clear, urgent and non-negotiable objective.