Science and technology play an important role in modern medicine and experience shows that, although school students and their relatives are likely to have experienced some of the complex procedures available today, they are generally not aware of the science behind them. Demonstrations that link school science to medical procedures can therefore be a powerful way of both reinforcing some basic physics ideas and of encouraging students to think about careers in medical physics or engineering. Simple, and often low-budget, demonstrations relating to X-rays, ultrasound, endoscopy and pulse oximetry are described, along with suggestions for further sources of information.