The present invention relates to a composition comprising a mixture of a polymeric biguanide polymer and an alkyl and/or dialkyl oxyethylene methyl ammonium salt for use as a medicament, in particular for use in treating, preventing or ameliorating a fungal disease such as aspergillosis. The present invention provides a method of treating, preventing and/or ameliorating a medical condition comprising administering the composition of the present invention to a human or animal in need thereof. A mechanical device comprising said composition is also provided.