Every year, millions of animals worldwide are subjected to painful and deadly animal experiments. Animal testing supporters often justify these procedures with their alleged necessity for advancing biomedical sciences and developing new drugs and therapies for human patients. However, multiple studies, statistics, and reports clearly show that the data obtained in animal experiments are unreliable and cannot be confidently transferred to human biology and disease. Here, I will present several central scientifically-based arguments against animal testing. We will see that animal testing is unnecessary and contra-productive and can jeopardize patient safety when it comes to drug development. I will comment on some frequent but inaccurate or misleading arguments used by animal testing supporters. Furthermore, we will see examples of modern and precise animal-free biomedical methods and models. Finally, we discuss what each of us can do to bring an end to animal testing.