SUMMARYIn April 1976, we discovered that the in vitro fungistatic action of Gamastan toPhialophora dermatitidiscould be inhibited by the goat antiserum to human immunoglobulins IgG, IgM and IgA. In July and October last year we proved on several occasions that the experimental cladosporiosis of white Swiss mouse caused byP. dermatitidiscould be prevented or cured by the application of Gamastan intravenously. Clinical therapeutic trials against mycoses with Gamastan and other human immnoglobulin preparations are being made.