As a rule, curative operations require the patient's consent. Determined by the expansion of surgical possibilities, the kind and frequency of specific complications are subjected to constant changes. The physician is encouraged to explain therapeutic methods as well as the probability of complications within the patient's grasp. It has been investigated to what extent methods of artificial intelligence (AI) are suited for assisting the physician in this task. For this purpose, a comprehensive list of surgical complications as reported in research literature has been compiled. The list has been transferred into a hierarchical structure which can be depicted as a rule tree classified according to topographic aspects. In each otolaryngological operation, the reported complications can be classed with these rules. By employing an expert system (Fig. 1), the physician is capable of compiling an individualized document of agreement (Fig. 2) which serves as a basis for the explanatory talk with the patient.