The recent development in the treatment of the urinary stones has much to do with underwater shock waves. And urologists have become more aggressive in using this modality in the treatment of the complicated stone patient. However, controversy persists regarding the extent to which the applied voltage and shock wave number interact to induce both cellular injury and stone fragmentation and also the appropriate timing of repeat lithotripsy treatments. It is very short time since underwater shock wave has been initially applied to human body. The effects of the shock wave on the microstructure of the tissues are poorly understood. The questions, what happens at the F2 focus and what happens to the energy after arriving at the F2, remain unclear. The bioeffects of ESWL should be more and more scrutinized.