The study lays emphasis on the significance and actuality of infections, especially in coincidence with immunodeficient states. Candidosis, mycotic diseases caused by moulds, systemic mycoses, and onychomycoses represent the major problems of modern mycology. They require usually a long-term therapy by means of highly active antimycotics. Consequently, an entire series of undesirable side-effects supervene. External applications result most frequently in contact eczemas and therefore often require preventive patch tests. Oral administration results in general hepatic, renal, hematologic and other impairments which require the monitoring of the latter parameters during therapy. Finally a considerable significance is ascribed to interaction with other simultaneously applied drugs with the antimycotics. (Tab. 1, Ref. 83.)