Abstract: The present invention relates to a spray-dried composition comprising as an active ingredient at least one member protein of the collectin family or its functional equivalent for treating and preventing microbial infectious diseases. The present invention also relates to a method for producing the same composition. The composition produced by the method of the present invention is effective in suppressing infections caused by viruses, bacteria, fungi, and parasites. Since the composition is developed in a form suitable for inhalation, it can directly provide the active ingredient to the sites of infection from these microbes, and thus treat and prevent respiratory infections and external wounds.