The tissue safety of a new shock wave generator, the Siemens C generator, was investigated in a porcine model. The tissue and functional effects of single treatments as well as retreatments were evaluated after 2 and 14 days. Quantitative morphologic and functional studies suggest that this device can be applied at its maximum energy up to 4000 shock waves (SW) without provoking damage that would lead to clinical concern. From this study, it appears justified to apply this device to patients suffering from stone disease to assess the clinical efficiency.