[The 1, 2, 3 of laboratory animal experimentation].

The slow scientific development in Latin America in recent decades has delayed the incorporation of laboratory animal experimentation; however, this situation has started to change. Today, extraordinary scientific progress is evident, which has promoted the introduction and increased use of laboratory animals as an important tool for the advancement of biomedical sciences. In the aftermath of this boom, the need to provide the scientific community with training and guidance in all aspects related to animal experimentation has arisen. It is the responsibility of each country to regulate this practice, for both bioethical and legal reasons, to ensure consideration of the animals' rights and welfare. The following manuscript is the result of papers presented at the International Workshop on Laboratory Animal Testing held at the Technical University of Ambato, Ecuador; it contains information regarding the current state of affairs in laboratory animal testing and emphasizes critical aspects such as main species used, ethical and legal principles, and experimental and alternative designs for animal use. These works aim to ensure good practices that should define scientific work. This document will be relevant to both researchers who aim to newly incorporate animal testing into their research and those who seek to update their knowledge.