Animal experimentation is a vast ecosystem that tries to make different issues such as legislative, ethical and scientific coexist. Research in animal experimentation has made many strides thanks to the 3Rs principle and the attached legislative decrees, but for this very reason, it needs to be evenly implemented both among the countries that have adhered to the decrees and among the team members who design and execute the experimental practice. In this article, we emphasize the importance of the 3Rs principle’s application, with a particular focus on the concept of Reduction and related key aspects that can best be handled with the contribution of experts from different fields.