We present a novel approach for enhancing images and video used in endoscopic surgery so that they are better able to convey shape. Our method is based on multi-flash imaging, in which multiple light sources are strategically positioned to cast shadows along depth discontinuities. We describe designs for achieving multi-flash imaging using multiple endoscopes as well as in single endoscopes. Multi-flash photography can also be used for creating medical illustrations. By highlighting the detected edges, suppressing unnecessary details, or combining features from multiple images, the resulting images convey more clearly the 3D structure of the subject. The method is easy to implement both in software and hardware, and can operate in realtime.