[Unexpected and undesirable treatment results].

The most frequent causes of unexpected and undesired results of treatment are due to insufficient information of the patient, furthermore, apart from technical deficiencies, to insufficient attention and experience of the physician, and to erroneous evaluation of the situation, especially with measuring out a dose of treatment-"medicus curat". On the other hand "natura sanat" comprises spontaneous healing. It's reactions of adaptation to functional stress are just partially known and, therefore, cannot be controlled safely. With insufficient incorporation of the cybernetic systems of the tissues into our planning of operations counter-reactions have to be expected, resulting in unphysiological, "unsound" operative procedures. They are characterised by relative frequent recurrences. The chances to reduce unexpected and undesired results in the "curative" and "sanative" sector are outlined. The personal experience remains most important.