A small, clear plastic chip with red and blue ‘veins’ could end, or at least drastically decrease, drug testing on animals. The chips mimic human organs, and allow researchers to experiment with drugs. With the chip, researchers can introduce diseases and treatments, and observe how the blood and cells respond. This is good new for animals. When using the chips for testing, fewer animals will be needed in the laboratory. Also, animals have different metabolism, structures and body functions than humans, so animal testing could never give an accurate indication of how effective drugs will be for humans. Organs-on-a-chip can solve this problem, too.