Tests on animals can provide much information – for instance they can help to advance scientific knowledge, understanding of diseases, and to investigate the development of new medicines. Non-animal alternative methods are used to gain this information whenever possible. However, while improved biological knowledge, technological advances, computer simulations and test tube methods allow significant reduction of the number of animals used, these methods are yet to fully replicate the complexity and reactions of a living organism.
And also: What is animal testing exactly?
And also: What are the key issues?