Abstract: The disclosure relates to use of alginate oligomers to enhance the effects of antifungal agents. The invention provides a method to improve the efficacy of an antifungal agent against a fungus, said method comprising using said antifungal agent together with an alginate oligomer. The fungus may be on an animate or inanimate surface and both medical and non-medical uses and methods are provided. In one aspect the invention provides an alginate oligomer for use together with at least one antifungal agent in treating a subject infected, suspected to be infected, or at risk of infection, with a fungus. In another aspect the method can be used to combat fungal contamination of a site e.g., for disinfection and cleaning purposes.