The better understanding of generation of by-products during laser application allows a rough risk assessment, which in turn results in a number of recommendations and guidelines. The main attention is directed to smoke evacuation systems in connection with sufficient room ventilation, both being obligatory for any invasive laser therapy. Minimal requirements and optimal use of such units are discussed and practical examples are presented. The important role of personal protection measures is pointed out. These measures are not new and more or less practiced in the past. However, they have been justified now in detail by the comprehensive investigations during the STILMED project.