Efficacy studies demonstrated that PS (sulphatated polysaccharides) named C3 and C23 significantly competed with glycosaminoglycans (GAG) and inhibited markers of inflammation induced by acute and chronic lung infection in murine models infected by Pseudomonas aeruginosa. In addition, they significantly reduced P. aeruginosa burden during chronic lung infection. C3 and C23 were administrated to mice by subcutaneous way and their pharmacokinetic characteristics were studied. Analysis in human respiratory samples showed that GAG, including Heparin Sulphate (HS), are present in the airways of CF patients and they correlate with markers of inflammation and tissue damage. These data support the further evaluation of C3 and C23 as novel therapeutic molecules to counteract excessive inflammation induced by P. aeruginosa pulmonary infections in CF patients.