Several activities regarding guidelines have been developed in Germany within a short time. It is desirable especially in the field of oncology that procedures are stated as proven effective, proven ineffective, and possibly effective by using procedures of evidence based medicine. However, the low impact of guidelines on the medical practice has to be taken into account. The kind of errors of known deviations should decrease the expectations. This altogether should motivate for a closer look what really happens in the daily routine. It should also reflect the hospital's and physician's outcome and might provide hints to medical standards. Improving the still insufficient documentation, which may describe quality of care, can provide important features. This has to be remembered when undertaking activities regarding guidelines.