A summary of five years of experimental and clinical mycological work in Berlin (West) is presented. The subjects of this research include: Soil of potted indoor plants as a habitat for aspergilli; exposure of sensitive patients suffering from different basic diseases to Aspergillus spores; polyene-producing streptomycetes beside aspergilli in the rhizosphere of potted plants and their role; and ecological and clinical significance of atypical Aspergillus strains isolated from clinical specimens. Reference is also made to the role of nuts as source of infection and as a baiting technique.