We studied 20 patients with cluster headache (11 males, 9 females) and 10 subjects free from this disorder. Nasal cavities were endoscopically studied to evaluate the mucociliary transport, pH, IgG, IgA and IgM levels in nasal secretion and in serum, and Na, K and Cl serum levels. We observed in all patients in the study group in comparison with the control group an increase of pH, and of serum IgA and IgM levels (but not of IgG). Na, K, and Cl serum levels in the patients with cluster headache were lower than those in the control subjects.