The invention relates to the use of a synergistic combination of at least one ion selected from the group including hypothiocyanites and/or hypohalites and of lactoferrin for preparing a pharmaceutical composition for treating cystic fibrosis. In one embodiment, the lactoferrin is one having a purity higher than 95% and substantially free of lipopolysaccharides, endotoxins, and angiogenins, and having an iron saturation level higher than 15%.
