The paradigm used by pharmaceutical companies to discover and develop new drugs is broken. Clinical studies take years to complete and testing a single compound can cost more than $2 million. Meanwhile, innumerable animal lives are lost, and the process often fails to predict human responses because traditional animal models do not accurately mimic human physiology. For these reasons, the pharmaceutical industry needs alternative ways to screen drug candidates in the laboratory. Microchips, called organs-on-chips, could one day form an accurate alternative to traditional animal testing. How is emulating human systems on microchips changing the drug development process?