The observations made by Paracelsus concerning the dose-effect relationship of poison are generally just as applicable to health- threatening vibration. With regard to kind, intensity, and duration of the vibration, the "dose" is decisive as to whether the conse- quences are detrimental, unmeaningful, or tolerable with respect to health. This law of nature determines the tasks and goals of those whose aim is to safeguard health. Researchers worldwide have been occupying themselves with this many-faceted question for some time: how mechanical vibration affects the human organism and at what point damage occurs. If prevention in occupational medicine is to succeed, it is most important that the gaps in our present knowledge be closed, for if technical preventive measures are to be effective and preventive means in occupational medicine successful, they must be based on reliable and complete findings. Whenever many independent researchers have worked in a given field for a long period, a comprehensive intermediate as- sessment is appropriate to evaluate the level achieved and the direction the research is going. In the area of hand-arm vibration, this evaluation has already been carried out, and the response aroused by this particular research report had led to a demand for a comparable evaluation of the research results on whole-body vibration. This report presents clearly and exhaustively the current status of international knowledge, as well as the questions that remain to be answered.